Computer Security Incident Handling Guide Recommendati

Computer Security
Incident Handling Guide
Recommendations of the National Institute
of Standards and Technology
Paul Cichonski
Tom Millar
Tim Grance
Karen Scarfone
Special Publication 800-61
Revision 2
http://dx.doi.org/10.6028/NIST.SP.800-61r2
NIST Special Publication 800-61
Revision 2
Computer Security Incident Handling
Guide
Recommendations of the National

Institute of Standards and Technology
Paul Cichonski
Computer Security Division
Information Technology Laboratory
National Institute of Standards and Technology
Gaithersburg, MD
Tom Millar
United States Computer Emergency Readiness Team
National Cyber Security Division
Department of Homeland Security
Tim Grance
Computer Security Division
Information Technology Laboratory
Gaithersburg, MD
Karen Scarfone
Scarfone Cybersecurity

C O M P U T E R S E C U R I T Y
August 2012
U.S. Department of Commerce
Rebecca Blank, Acting Secretary
Patrick D. Gallagher,
Under Secretary of Commerce for Standards and Technology
and Director
karenw
Typewritten Text
COMPUTER SECURITY INCIDENT HANDLING GUIDE
ii
Reports on Computer Systems Technology

The Information Technology Laboratory (ITL) at the National
Institute of Standards and Technology
(NIST) promotes the U.S. economy and public welfare by
providing technical leadership for the Nation’s
measurement and standards infrastructure. ITL develops tests,
test methods, reference data, proof of
concept implementations, and technical analyses to advance the
development and productive use of
information technology. ITL’s responsibilities include the
development of management, administrative,
technical, and physical standards and guidelines for the cost-
effective security and privacy of other than
national security-related information in Federal information
systems. The Special Publication 800-series
reports on ITL’s research, guidelines, and outreach efforts in
information system security, and its
collaborative activities with industry, government, and
academic organizations.

iii
Authority
This publication has been developed by NIST to further its
statutory responsibilities under the Federal
Information Security Management Act (FISMA), Public Law
(P.L.) 107-347. NIST is responsible for
developing information security standards and guidelines,
including minimum requirements for Federal
information systems, but such standards and guidelines shall not
apply to national security systems
without the express approval of appropriate Federal officials
exercising policy authority over such
systems. This guideline is consistent with the requirements of
the Office of Management and Budget
(OMB) Circular A-130, Section 8b(3), Securing Agency
Information Systems, as analyzed in Circular A-
130, Appendix IV: Analysis of Key Sections. Supplemental
information is provided in Circular A-130,
Appendix III, Security of Federal Automated Information
Resources.
Nothing in this publication should be taken to contradict the
standards and guidelines made mandatory
and binding on Federal agencies by the Secretary of Commerce

under statutory authority. Nor should
these guidelines be interpreted as altering or superseding the
existing authorities of the Secretary of
Commerce, Director of the OMB, or any other Federal official.
This publication may be used by
nongovernmental organizations on a voluntary basis and is not
subject to copyright in the United States.
Attribution would, however, be appreciated by NIST.
National Institute of Standards and Technology Special
Publication 800-61 Revision 2
Natl. Inst. Stand. Technol. Spec. Publ. 800-61 Revision 2, 79
pages (Aug. 2012)
CODEN: NSPUE2
Comments on this publication may be submitted to:
Attn: Computer Security Division, Information Technology

Laboratory
100 Bureau Drive (Mail Stop 8930), Gaithersburg, MD 20899-
8930
Certain commercial entities, equipment, or materials may be
identified in this document in order to describe an
experimental procedure or concept adequately. Such
identification is not intended to imply recommendation or
endorsement by NIST, nor is it intended to imply that the
entities, materials, or equipment are necessarily the
best available for the purpose.
There may be references in this publication to other
publications currently under development by NIST in
accordance with its assigned statutory responsibilities. The
information in this publication, including concepts
and methodologies, may be used by Federal agencies even
before the completion of such companion
publications. Thus, until each publication is completed, current
requirements, guidelines, and procedures, where
they exist, remain operative. For planning and transition
purposes, Federal agencies may wish to closely follow
the development of these new publications by NIST.
Organizations are encouraged to review all draft publications
during public comment periods and provide

feedback to NIST. All NIST publications, other than the ones
noted above, are available at
http://csrc.nist.gov/publications.
karenw
Typewritten Text
iv
Abstract
Computer security incident response has become an important
component of information technology (IT)
programs. Because performing incident response effectively is a
complex undertaking, establishing a
successful incident response capability requires substantial
planning and resources. This publication
assists organizations in establishing computer security incident
response capabilities and handling
incidents efficiently and effectively. This publication provides
guidelines for incident handling,
particularly for analyzing incident-related data and determining

the appropriate response to each incident.
The guidelines can be followed independently of particular
hardware platforms, operating systems,
protocols, or applications.
Keywords
computer security incident; incident handling; incident
response; information security
v
Acknowledgments
The authors, Paul Cichonski of the National Institute of
Standards and Technology (NIST), Tom Millar of
the United States Computer Emergency Readiness Team (US-
CERT), Tim Grance of NIST, and Karen
Scarfone of Scarfone Cybersecurity wish to thank their
colleagues who reviewed drafts of this document
and contributed to its technical content, including John
Banghart of NIST; Brian Allen, Mark Austin,
Brian DeWyngaert, Andrew Fuller, Chris Hallenbeck, Sharon

Kim, Mischel Kwon, Lee Rock, Richard
Struse, and Randy Vickers of US-CERT; and Marcos Osorno of
the Johns Hopkins University Applied
Physics Laboratory. A special acknowledgment goes to Brent
Logan of US-CERT for his graphics
assistance. The authors would also like to thank security experts
Simon Burson, Anton Chuvakin
(Gartner), Fred Cohen (Fred Cohen & Associates), Mariano M.
del Rio (SIClabs), Jake Evans (Tripwire),
Walter Houser (SRA), Panos Kampanakis (Cisco), Kathleen
Moriarty (EMC), David Schwalenberg
(National Security Agency), and Wes Young (Research and
Education Networking Information Sharing
and Analysis Center [REN-ISAC]), as well as representatives of
the Blue Glacier Management Group, the
Centers for Disease Control and Prevention, the Department of
Energy, the Department of State, and the
Federal Aviation Administration for their particularly valuable
comments and suggestions.
The authors would also like to acknowledge the individuals that
contributed to the previous versions of
the publication. A special thanks goes to Brian Kim of Booz
Allen Hamilton, who co-authored the
original version; to Kelly Masone of Blue Glacier Management

Group, who co-authored the first revision;
and also to Rick Ayers, Chad Bloomquist, Vincent Hu, Peter
Mell, Scott Rose, Murugiah Souppaya, Gary
Stoneburner, and John Wack of NIST; Don Benack and Mike
Witt of US-CERT; and Debra Banning,
Pete Coleman, Alexis Feringa, Tracee Glass, Kevin Kuhlkin,
Bryan Laird, Chris Manteuffel, Ron
Ritchey, and Marc Stevens of Booz Allen Hamilton for their
keen and insightful assistance throughout the
development of the document, as well as Ron Banerjee and
Gene Schultz for their work on a preliminary
draft of the document. The authors would also like to express
their thanks to security experts Tom Baxter
(NASA), Mark Bruhn (Indiana University), Brian Carrier
(CERIAS, Purdue University), Eoghan Casey,
Johnny Davis, Jr. (Department of Veterans Affairs), Jim Duncan
(BB&T), Dean Farrington (Wells Fargo
Bank), John Hale (University of Tulsa), Georgia Killcrece
(CERT
®
/CC), Barbara Laswell (CERT
®
/CC),
Pascal Meunier (CERIAS, Purdue University), Jeff Murphy
(University of Buffalo), Todd O’Boyle

(MITRE), Marc Rogers (CERIAS, Purdue University), Steve
Romig (Ohio State University), Robin
Ruefle (CERT
®
/CC), Gene Schultz (Lawrence Berkeley National Laboratory),
Michael Smith (US-
CERT), Holt Sorenson, Eugene Spafford (CERIAS, Purdue
University), Ken van Wyk, and Mark Zajicek
(CERT
®
/CC), as well as representatives of the Department of the
Treasury, for their particularly valuable
comments and suggestions.
vi
Table of Contents
Executive Summary
...............................................................................................
.................. 1
1. Introduction
...............................................................................................
....................... 4

1.1 Authority
...............................................................................................
..................... 4
1.2 Purpose and Scope
...............................................................................................
.... 4
1.3 Audience
...............................................................................................
.................... 4
1.4 Document Structure
...............................................................................................
... 4
2. Organizing a Computer Security Incident Response
Capability ................................... 6
2.1 Events and Incidents
...............................................................................................
.. 6
2.2 Need for Incident Response
...................................................................................... 6
2.3 Incident Response Policy, Plan, and Procedure Creation
.......................................... 7
2.3.1 Policy
Elements.................................................................................
............ 7
2.3.2 Plan Elements
...............................................................................................
8
2.3.3 Procedure Elements
...................................................................................... 8
2.3.4 Sharing Information With Outside Parties
...................................................... 9

2.4 Incident Response Team Structure
......................................................................... 13
2.4.1 Team Models
...............................................................................................
13
2.4.2 Team Model
Selection.................................................................................
.14
2.4.3 Incident Response Personnel
.......................................................................16
2.4.4 Dependencies within Organizations
.............................................................17
2.5 Incident Response Team Services
.......................................................................... 18
2.6 Recommendations
...............................................................................................
... 19
3. Handling an Incident
...............................................................................................
........21
3.1 Preparation
...............................................................................................
............... 21
3.1.1 Preparing to Handle Incidents
......................................................................21
3.1.2 Preventing Incidents
.....................................................................................23
3.2 Detection and Analysis
............................................................................................
25
3.2.1 Attack Vectors
..............................................................................................

25
3.2.2 Signs of an Incident
......................................................................................26
3.2.3 Sources of Precursors and Indicators
...........................................................27
3.2.4 Incident Analysis
..........................................................................................28
3.2.5 Incident Documentation
................................................................................30
3.2.6 Incident Prioritization
....................................................................................32
3.2.7 Incident Notification
......................................................................................33
3.3 Containment, Eradication, and
Recovery................................................... .............. 35
3.3.1 Choosing a Containment Strategy
................................................................35
3.3.2 Evidence Gathering and Handling
................................................................36
3.3.3 Identifying the Attacking Hosts
.....................................................................37
3.3.4 Eradication and Recovery
............................................................................37
3.4 Post-Incident Activity
...............................................................................................
38
3.4.1 Lessons Learned
..........................................................................................38
3.4.2 Using Collected Incident Data
......................................................................39
3.4.3 Evidence Retention
......................................................................................41
3.5 Incident Handling Checklist

..................................................................................... 42
3.6 Recommendations
...............................................................................................
... 42
4. Coordination and Information Sharing
..........................................................................45
vii
4.1 Coordination
...............................................................................................
............. 45
4.1.1 Coordination Relationships
..........................................................................46
4.1.2 Sharing Agreements and Reporting Requirements
......................................47
4.2 Information Sharing Techniques
.............................................................................. 48
4.2.1 Ad Hoc
...............................................................................................
..........48
4.2.2 Partially Automated
......................................................................................48
4.2.3 Security Considerations
...............................................................................49
4.3 Granular Information Sharing
.................................................................................. 49
4.3.1 Business Impact Information
........................................................................49

4.3.2 Technical Information
...................................................................................50
4.4 Recommendations
...............................................................................................
... 51
List of Appendices
Appendix A— Incident Handling Scenarios
..........................................................................52
A.1 Scenario Questions
...............................................................................................
.. 52
A.2 Scenarios
...............................................................................................
................. 53
Appendix B— Incident-Related Data Elements
.....................................................................58
B.1 Basic Data Elements
...............................................................................................
58
B.2 Incident Handler Data Elements
.............................................................................. 59
Appendix C— Glossary
...............................................................................................
...........60
Appendix D— Acronyms
...............................................................................................
.........61

Appendix E—
Resources................................................................................
........................63
Appendix F— Frequently Asked Questions
..........................................................................65
Appendix G— Crisis Handling Steps
.....................................................................................68
Appendix H— Change Log
...............................................................................................
......69
List of Figures
Figure 2-1. Communications with Outside Parties
.....................................................................10
Figure 3-1. Incident Response Life Cycle
..................................................................................21
Figure 3-2. Incident Response Life Cycle (Detection and
Analysis) ...........................................25
Figure 3-3. Incident Response Life Cycle (Containment,
Eradication, and Recovery) ...............35
Figure 3-4. Incident Response Life Cycle (Post-Incident
Activity) ..............................................38
Figure 4-1. Incident Response Coordination

.............................................................................46
viii
List of Tables
Table 3-1. Common Sources of Precursors and Indicators
.......................................................27
Table 3-2. Functional Impact Categories
...................................................................................33
Table 3-3. Information Impact Categories
.................................................................................33
Table 3-4. Recoverability Effort Categories
...............................................................................33
Table 3-5. Incident Handling Checklist
......................................................................................42
Table 4-1. Coordination Relationships
......................................................................................47

1
Executive Summary
Computer security incident response has become an important
component of information technology (IT)
programs. Cybersecurity-related attacks have become not only
more numerous and diverse but also more
damaging and disruptive. New types of security-related
incidents emerge frequently. Preventive activities
based on the results of risk assessments can lower the number of
incidents, but not all incidents can be
prevented. An incident response capability is therefore
necessary for rapidly detecting incidents,
minimizing loss and destruction, mitigating the weaknesses that
were exploited, and restoring IT services.
To that end, this publication provides guidelines for incident
handling, particularly for analyzing incident-
related data and determining the appropriate response to each
incident. The guidelines can be followed
independently of particular hardware platforms, operating
systems, protocols, or applications.
Because performing incident response effectively is a complex
undertaking, establishing a successful

incident response capability requires substantial planning and
resources. Continually monitoring for
attacks is essential. Establishing clear procedures for
prioritizing the handling of incidents is critical, as is
implementing effective methods of collecting, analyzing, and
reporting data. It is also vital to build
relationships and establish suitable means of communication
with other internal groups (e.g., human
resources, legal) and with external groups (e.g., other incident
response teams, law enforcement).
This publication assists organizations in establishing computer
security incident response capabilities and
handling incidents efficiently and effectively. This revision of
the publication, Revision 2, updates
material throughout the publication to reflect the changes in
attacks and incidents. Understanding threats
and identifying modern attacks in their early stages is key to
preventing subsequent compromises, and
proactively sharing information among organizations regarding
the signs of these attacks is an
increasingly effective way to identify them.
Implementing the following requirements and recommendations
should facilitate efficient and effective
incident response for Federal departments and agencies.

Organizations must create, provision, and operate a formal
incident response capability. Federal
law requires Federal agencies to report incidents to the United
States Computer Emergency
Readiness Team (US-CERT) office within the Department of
Homeland Security (DHS).
The Federal Information Security Management Act (FISMA)
requires Federal agencies to establish
incident response capabilities. Each Federal civilian agency
must designate a primary and secondary point
of contact (POC) with US-CERT and report all incidents
consistent with the agency’s incident response
policy. Each agency is responsible for determining how to
fulfill these requirements.
Establishing an incident response capability should include the
following actions:
reporting
etting guidelines for communicating with outside parties
regarding incidents

between the incident response team and other
groups, both internal (e.g., legal department) and external (e.g.,
law enforcement agencies)
provide
2
Organizations should reduce the frequency of incidents by
effectively securing networks, systems,
and applications.
Preventing problems is often less costly and more effective than
reacting to them after they occur. Thus,
incident prevention is an important complement to an incident
response capability. If security controls are
insufficient, high volumes of incidents may occur. This could
overwhelm the resources and capacity for
response, which would result in delayed or incomplete recovery
and possibly more extensive damage and
longer periods of service and data unavailability. Incident
handling can be performed more effectively if
organizations complement their incident response capability

with adequate resources to actively maintain
the security of networks, systems, and applications. This
includes training IT staff on complying with the
organization’s security standards and making users aware of
policies and procedures regarding
appropriate use of networks, systems, and applications.
Organizations should document their guidelines for interactions
with other organizations regarding
incidents.
During incident handling, the organization will need to
communicate with outside parties, such as other
incident response teams, law enforcement, the media, vendors,
and victim organizations. Because these
communications often need to occur quickly, organizations
should predetermine communication
guidelines so that only the appropriate information is shared
with the right parties.
Organizations should be generally prepared to handle any
incident but should focus on being
prepared to handle incidents that use common attack vectors.
Incidents can occur in countless ways, so it is infeasible to
develop step-by-step instructions for handling
every incident. This publication defines several types of

incidents, based on common attack vectors; these
categories are not intended to provide definitive classification
for incidents, but rather to be used as a
basis for defining more specific handling procedures. Different
types of incidents merit different response
strategies. The attack vectors are:
removable media (e.g., flash drive, CD) or a
peripheral device.
mploys brute force methods to
compromise, degrade, or destroy systems,
networks, or services.
-based
application.
attachment.
cident resulting from violation of an
organization’s acceptable usage
policies by an authorized user, excluding the above categories.
device or media used by the
organization, such as a laptop or smartphone.
categories.

3
Organizations should emphasize the importance of incident
detection and analysis throughout the
organization.
In an organization, millions of possible signs of incidents may
occur each day, recorded mainly by
logging and computer security software. Automation is needed
to perform an initial analysis of the data
and select events of interest for human review. Event
correlation software can be of great value in
automating the analysis process. However, the effectiveness of
the process depends on the quality of the
data that goes into it. Organizations should establish logging
standards and procedures to ensure that
adequate information is collected by logs and security software
and that the data is reviewed regularly.
Organizations should create written guidelines for prioritizing
incidents.
Prioritizing the handling of individual incidents is a critical
decision point in the incident response
process. Effective information sharing can help an organization
identify situations that are of greater

severity and demand immediate attention. Incidents should be
prioritized based on the relevant factors,
such as the functional impact of the incident (e.g., current and
likely future negative impact to business
functions), the information impact of the incident (e.g., effect
on the confidentiality, integrity, and
availability of the organization’s information), and the
recoverability from the incident (e.g., the time and
types of resources that must be spent on recovering from the
incident).
Organizations should use the lessons learned process to gain
value from incidents.
After a major incident has been handled, the organization
should hold a lessons learned meeting to review
the effectiveness of the incident handling process and identify
necessary improvements to existing
security controls and practices. Lessons learned meetings can
also be held periodically for lesser incidents
as time and resources permit. The information accumulated
from all lessons learned meetings should be
used to identify and correct systemic weaknesses and
deficiencies in policies and procedures. Follow -up
reports generated for each resolved incident can be important
not only for evidentiary purposes but also

for reference in handling future incidents and in training new
team members.
4
1. Introduction
1.1 Authority
The National Institute of Standards and Technology (NIST)
developed this document in furtherance of its
statutory responsibilities under the Federal Information Security
Management Act (FISMA) of 2002,
Public Law 107-347.
NIST is responsible for developing standards and guidelines,
including minimum requirements, for
providing adequate information security for all agency
operations and assets, but such standards and
guidelines shall not apply to national security systems. This
guideline is consistent with the requirements
of the Office of Management and Budget (OMB) Circular A-
130, Section 8b(3), “Securing Agency

Information Systems,” as analyzed in A-130, Appendix IV:
Analysis of Key Sections. Supplemental
information is provided in A-130, Appendix III.
This guideline has been prepared for use by Federal agencies. It
may be used by nongovernmental
organizations on a voluntary basis and is not subject to
copyright, though attribution is desired.
Nothing in this document should be taken to contradict
standards and guidelines made mandatory and
binding on Federal agencies by the Secretary of Commerce
under statutory authority, nor should these
guidelines be interpreted as altering or superseding the existing
authorities of the Secretary of Commerce,
Director of the OMB, or any other Federal official.
1.2 Purpose and Scope
This publication seeks to assist organizations in mitigating the
risks from computer security incidents by
providing practical guidelines on responding to incidents
effectively and efficiently. It includes guidelines
on establishing an effective incident response program, but the
primary focus of the document is
detecting, analyzing, prioritizing, and handling incidents.
Organizations are encouraged to tailor the

recommended guidelines and solutions to meet their specific
security and mission requirements.
1.3 Audience
This document has been created for computer security incident
response teams (CSIRTs), system and
network administrators, security staff, technical support staff,
chief information security officers (CISOs),
chief information officers (CIOs), computer security program
managers, and others who are responsible
for preparing for, or responding to, security incidents.
1.4 Document Structure
The remainder of this document is organized into the following
sections and appendices:
possible incident response team
structures, and highlights other groups within an organization
that may participate in incident
handling.
provides advice for performing incident
handling more effectively, particularly incident detection and
analysis.
need for incident response
coordination and information sharing.

5
questions for use in incident response tabletop
discussions.
s lists of suggested data fields to collect
for each incident.
respectively.
planning and performing incident response.
covers frequently asked questions about incident
response.
computer security incident-related crisis.
since the previous revision.
6
2. Organizing a Computer Security Incident Response
Capability

Organizing an effective computer security incident response
capability (CSIRC) involves several major
decisions and actions. One of the first considerations should be
to create an organization-specific
definition of the term “incident” so that the scope of the term is
clear. The organization should decide
what services the incident response team should provide,
consider which team structures and models can
provide those services, and select and implement one or more
incident response teams. Incident response
plan, policy, and procedure creation is an important part of
establishing a team, so that incident response
is performed effectively, efficiently, and consistently, and so
that the team is empowered to do what needs
to be done. The plan, policies, and procedures should reflect the
team’s interactions with other teams
within the organization as well as with outside parties, such as
law enforcement, the media, and other
incident response organizations. This section provides not only
guidelines that should be helpful to
organizations that are establishing incident response
capabilities, but also advice on maintaining and
enhancing existing capabilities.

2.1 Events and Incidents
An event is any observable occurrence in a system or network.
Events include a user connecting to a file
share, a server receiving a request for a web page, a user
sending email, and a firewall blocking a
connection attempt. Adverse events are events with a negative
consequence, such as system crashes,
packet floods, unauthorized use of system privileges,
unauthorized access to sensitive data, and execution
of malware that destroys data. This guide addresses only
adverse events that are computer security-
related, not those caused by natural disasters, power failures,
etc.
A computer security incident is a violation or imminent threat
of violation
1
of computer security policies,
acceptable use policies, or standard security practices.
Examples of incidents
2
are:
connection requests to a web server, causing
it to crash.
rt” sent via
email that is actually malware; running the

tool has infected their computers and established connections
with an external host.
details will be released publicly if the
organization does not pay a designated sum of money.
through peer-to-peer file sharing services.
2.2 Need for Incident Response
Attacks frequently compromise personal and business data, and
it is critical to respond quickly and
effectively when security breaches occur. The concept of
computer security incident response has become
widely accepted and implemented. One of the benefits of having
an incident response capability is that it
supports responding to incidents systematically (i.e., following
a consistent incident handling
methodology) so that the appropriate actions are taken. Incident
response helps personnel to minimize
loss or theft of information and disruption of services caused by
incidents. Another benefit of incident
response is the ability to use information gained during incident
handling to better prepare for handling
1
An “imminent threat of violation” refers to a situation in

which the organization has a factual basis for believing that a
specific incident is about to occur. For example, the antivirus
software maintainers may receive a bulletin from the software
vendor, warning them of new malware that is rapidly spreading
across the Internet.
2
For the remainder of this document, the terms “incident” and
“computer security incident” are interchangeable.
7
future incidents and to provide stronger protection for systems
and data. An incident response capability
also helps with dealing properly with legal issues that may arise
during incidents.
Besides the business reasons to establish an incident response
capability, Federal departments and
agencies must comply with law, regulations, and policy
directing a coordinated, effective defense against
information security threats. Chief among these are the
following:
-130, Appendix III,
3
released in 2000, which directs Federal agencies to

“ensure that there is a capability to provide help to users when a
security incident occurs in the system
and to share information concerning common vulnerabilities and
threats. This capability shall share
information with other organizations … and should assist the
agency in pursuing appropriate legal
action, consistent with Department of Justice guidance.”
4
which requires agencies to have “procedures for detecting,
reporting, and
responding to security incidents” and establishes a centralized
Federal information security incident
center, in part to:
– “Provide timely technical assistance to operators of agency
information systems … including
guidance on detecting and handling information security
incidents …
– Compile and analyze information about incidents that threaten
information security …
– Inform operators of agency information systems about current
and potential information security
threats, and vulnerabilities … .”
Standards (FIPS) 200,
Minimum Security Requirements for Federal
Information and Information Systems

5
, March 2006, which specifies minimum security requirements
for Federal information and information systems, including
incident response. The specific
requirements are defined in NIST Special Publication (SP) 800-
53, Recommended Security Controls
for Federal Information Systems and Organizations.
-07-16, Safeguarding Against and
Responding to the Breach of Personally
Identifiable Information
6
, May 2007, which provides guidance on reporting security
incidents that
involve PII.
2.3 Incident Response Policy, Plan, and Procedure Creation
This section discusses policies, plans, and procedures related to
incident response, with an emphasis on
interactions with outside parties.
2.3.1 Policy Elements
Policy governing incident response is highly individualized to
the organization. However, most policies
include the same key elements:

3
http://www.whitehouse.gov/omb/circulars/a130/a130trans4.html
4
http://csrc.nist.gov/drivers/documents/FISMA-final.pdf
5
http://csrc.nist.gov/publications/PubsFIPS.html
6
http://www.whitehouse.gov/omb/memoranda/fy2007/m07-
16.pdf
http://www.whitehouse.gov/omb/circulars/a130/a130trans4.html
http://csrc.nist.gov/drivers/documents/FISMA-final.pdf
http://www.whitehouse.gov/omb/memoranda/fy2007/m07-16.pdf
8
what circumstances)
responsibilities, and levels of authority; should

include the authority of the incident response team to confiscate
or disconnect equipment and to
monitor suspicious activity, the requirements for reporting
certain types of incidents, the requirements
and guidelines for external communications and information
sharing (e.g., what can be shared with
whom, when, and over what channels), and the handoff and
escalation points in the incident
management process
2.3.2 Plan Elements
Organizations should have a formal, focused, and coordinated
approach to responding to incidents,
including an incident response plan that provides the roadmap
for implementing the incident response
capability. Each organization needs a plan that meets its unique
requirements, which relates to the
organization’s mission, size, structure, and functions. The plan
should lay out the necessary resources and
management support. The incident response plan should include
the following elements:

roach to incident response
rest of the organization and with other
organizations
effectiveness
ident response capability
The organization’s mission, strategies, and goals for incident
response should help in determining the
structure of its incident response capability. The incident
response program structure should also be
discussed within the plan. Section 2.4.1 discusses the types of
structures.
Once an organization develops a plan and gains management
approval, the organization should
implement the plan and review it at least annually to ensure the
organization is following the roadmap for
maturing the capability and fulfilling their goals for incident

response.
2.3.3 Procedure Elements
Procedures should be based on the incident response policy and
plan. Standard operating procedures
(SOPs) are a delineation of the specific technical processes,
techniques, checklists, and forms used by the
incident response team. SOPs should be reasonably
comprehensive and detailed to ensure that the
9
priorities of the organization are reflected in response
operations. In addition, following standardized
responses should minimize errors, particularly those that might
be caused by stressful incident handling
situations. SOPs should be tested to validate their accuracy and
usefulness, then distributed to all team
members. Training should be provided for SOP users; the SOP
documents can be used as an instructional
tool. Suggested SOP elements are presented throughout Section
3.
2.3.4 Sharing Information With Outside Parties

Organizations often need to communicate with outside parties
regarding an incident, and they should do
so whenever appropriate, such as contacting law enforcement,
fielding media inquiries, and seeking
external expertise. Another example is discussing incidents with
other involved parties, such as Internet
service providers (ISPs), the vendor of vulnerable software, or
other incident response teams.
Organizations may also proactively share relevant incident
indicator information with peers to improve
detection and analysis of incidents. The incident response team
should discuss information sharing with
the organization’s public affairs office, legal department, and
management before an incident occurs to
establish policies and procedures regarding information sharing.
Otherwise, sensitive information
regarding incidents may be provided to unauthorized parties,
potentially leading to additional disruption
and financial loss. The team should document all contacts and
communications with outside parties for
liability and evidentiary purposes.
The following sections provide guidelines on communicating
with several types of outside parties, as
depicted in Figure 2-1. The double-headed arrows indicate that

either party may initiate communications.
See Section 4 for additional information on communicating with
outside parties, and see Section 2.4 for a
discussion of communications involving incident response
outsourcers.
10
Figure 2-1. Communications with Outside Parties
2.3.4.1 The Media
The incident handling team should establish media
communications procedures that comply with the
organization’s policies on media interaction and information
disclosure.
7
For discussing incidents with the
media, organizations often find it beneficial to designate a
single point of contact (POC) and at least one
backup contact. The following actions are recommended for
preparing these designated contacts and
should also be considered for preparing others who may be
communicating with the media:

regarding incidents, which should include the
importance of not revealing sensitive information, such as
technical details of countermeasures that
could assist other attackers, and the positive aspects of
communicating important information to the
public fully and effectively.
sensitivities regarding a particular
incident before discussing it with the media.
7
For example, an organization may want members of its public
affairs office and legal department to participate in all
incident discussions with the media.
11
that communications with the media are
consistent and up-to-date.
l procedures for handling media
inquiries.
handling exercises. The following are

examples of questions to ask the media contact:
– Who attacked you? Why?
– When did it happen? How did it happen? Did this happen
because you have poor security
practices?
– How widespread is this incident? What steps are you taking to
determine what happened and to
prevent future occurrences?
– What is the impact of this incident? Was any personally
identifiable information (PII) exposed?
What is the estimated cost of this incident?
2.3.4.2 Law Enforcement
One reason that many security-related incidents do not result in
convictions is that some organizations do
not properly contact law enforcement. Several levels of law
enforcement are available to investigate
incidents: for example, within the United States, Federal
investigatory agencies (e.g., the Federal Bureau
of Investigation [FBI] and the U.S. Secret Service), district
attorney offices, state law enforcement, and
local (e.g., county) law enforcement. Law enforcement agencies
in other countries may also be involved,
such as for attacks launched from or directed at locations
outside the US. In addition, agencies have an

Office of Inspector General (OIG) for investigation of violation
of the law within each agency. The
incident response team should become acquainted with its
various law enforcement representatives before
an incident occurs to discuss conditions under which incidents
should be reported to them, how the
reporting should be performed, what evidence should be
collected, and how it should be collected.
Law enforcement should be contacted through designated
individuals in a manner consistent with the
requirements of the law and the organization’s procedures.
Many organizations prefer to appoint one
incident response team member as the primary POC with law
enforcement. This person should be familiar
with the reporting procedures for all relevant law enforcement
agencies and well prepared to recommend
which agency, if any, should be contacted. Note that the
organization typically should not contact
multiple agencies because doing so might result in jurisdictional
conflicts. The incident response team
should understand what the potential jurisdictional issues are
(e.g., physical location—an organization
based in one state has a server located in a second state attacked
from a system in a third state, being used

remotely by an attacker in a fourth state).
2.3.4.3 Incident Reporting Organizations
FISMA requires Federal agencies to report incidents to the
United States Computer Emergency Readiness
Team (US-CERT),
8
which is a governmentwide incident response organization that
assists Federal
civilian agencies in their incident handling efforts. US-CERT
does not replace existing agency response
teams; rather, it augments the efforts of Federal civilian
agencies by serving as a focal point for dealing
with incidents. US-CERT analyzes the agency-provided
information to identify trends and indicators of
attacks; these are easier to discern when reviewing data from
many organizations than when reviewing
the data of a single organization.
8
http://www.us-cert.gov/
12

Each agency must designate a primary and secondary POC with
US-CERT and report all incidents
consistent with the agency’s incident response policy.
Organizations should create a policy that states
who is designated to report incidents and how the incidents
should be reported. Requirements, categories,
and timeframes for reporting incidents to US-CERT are on the
US-CERT website.
9
All Federal agencies
must ensure that their incident response procedures adhere to
US-CERT’s reporting requirements and that
the procedures are followed properly.
All organizations are encouraged to report incidents to their
appropriate CSIRTs. If an organization does
not have its own CSIRT to contact, it can report incidents to
other organizations, including Information
Sharing and Analysis Centers (ISACs). One of the functions of
these industry-specific private sector
groups is to share important computer security-related
information among their members. Several ISACs
have been formed for industry sectors such as Communications,
Electric Sector, Financial Services,
Information Technology, and Research and Education.

10
2.3.4.4 Other Outside Parties
An organization may want to discuss incidents with other
groups, including those listed below. When
reaching out to these external parties, an organization may want
to work through US-CERT or its ISAC,
as a “trusted introducer” to broker the relationship. It is l ikely
that others are experiencing similar issues,
and the trusted introducer can ensure that any such patterns are
identified and taken into consideration.
from its ISP in blocking a major network-
based attack or tracing its origin.
from an external organization’s IP
address space, incident handlers may want to talk to the
designated security contacts for the
organization to alert them to the activity or to ask them to
collect evidence. It is highly recommended
to coordinate such communications with US-CERT or an ISAC.
software vendor about suspicious
activity. This contact could include questions regarding the
significance of certain log entries or

known false positives for certain intrusion detection signatures,
where minimal information regarding
the incident may need to be revealed. More information may
need to be provided in some cases—for
example, if a server appears to have been compromised through
an unknown software vulnerability.
Software vendors may also provide information on known
threats (e.g., new attacks) to help
organizations understand the current threat environment.
experience an incident that is similar to ones
handled by other teams; proactively sharing information can
facilitate more effective and efficient
incident handling (e.g., providing advance warning, increasing
preparedness, developing situational
awareness). Groups such as the Forum of Incident Response and
Security Teams (FIRST)
11
, the
Government Forum of Incident Response and Security Teams
(GFIRST)
12
, and the Anti-Phishing
Working Group (APWG)
13

are not incident response teams, but they promote information
sharing
among incident response teams.
parties directly—for example, an outside
organization may contact the organization and claim that one of
the organization’s users is attacking
9
http://www.us-cert.gov/federal/reportingRequirements.html
10
See the National Council of ISACs website at
http://www.isaccouncil.org/ for a list of ISACs.
11
http://www.first.org/
12
GFIRST is specifically for Federal departments and agencies.
(http://www.us-cert.gov/federal/gfirst.html)
13
http://www.antiphishing.org/
http://www.us-cert.gov/federal/reportingRequirements.html
http://www.isaccouncil.org/
http://www.us-cert.gov/federal/gfirst.html

13
it. Another way in which external parties may be affected is if
an attacker gains access to sensitive
information regarding them, such as credit card information. In
some jurisdictions, organizations are
required to notify all parties that are affected by such an
incident. Regardless of the circumstances, it
is preferable for the organization to notify affected external
parties of an incident before the media or
other external organizations do so. Handlers should be careful
to give out only appropriate
information—the affected parties may request details about
internal investigations that should not be
revealed publicly.
OMB Memorandum M-07-16, Safeguarding Against and
Responding to the Breach of Personally
Identifiable Information, requires Federal agencies to develop
and implement a breach notification
policy for personally identifiable information (PII).
14
Incident handlers should understand how their

incident handling actions should differ when a PII breach is
suspected to have occurred, such as
notifying additional parties or notifying parties within a shorter
timeframe. Specific recommendations
for PII breach notification policies are presented in OMB
Memorandum M-07-16. Also, the National
Conference of State Legislatures has a list of state security
breach notification laws.
15
2.4 Incident Response Team Structure
An incident response team should be available for anyone who
discovers or suspects that an incident
involving the organization has occurred. One or more team
members, depending on the magnitude of the
incident and availability of personnel, will then handle the
incident. The incident handlers analyze the
incident data, determine the impact of the incident, and act
appropriately to limit the damage and restore
normal services. The incident response team’s success depends
on the participation and cooperation of
individuals throughout the organization. This section identifies
such individuals, discusses incident
response team models, and provides advice on selecting an
appropriate model.

2.4.1 Team Models
Possible structures for an incident response team include the
following:
team handles incidents throughout the
organization. This model is effective for small organizati ons
and for organizations with minimal
geographic diversity in terms of computing resources.
multiple incident response teams, each
responsible for a particular logical or physical segment of the
organization. This model is effective for
large organizations (e.g., one team per division) and for
organizations with major computing
resources at distant locations (e.g., one team per geographic
region, one team per major facility).
However, the teams should be part of a single coordinated entity
so that the incident response process
is consistent across the organization and information is shared
among teams. This is particularly
important because multiple teams may see components of the
same incident or may handle similar
incidents.

advice to other teams without having
authority over those teams—for example, a departmentwide
team may assist individual agencies’
teams. This model can be thought of as a CSIRT for CSIRTs.
Because the focus of this document is
14
http://www.whitehouse.gov/omb/memoranda/fy2007/m07-
16.pdf
15
http://www.ncsl.org/default.aspx?tabid=13489
http://www.whitehouse.gov/omb/memoranda/fy2007/m07-16.pdf
http://www.ncsl.org/default.aspx?tabid=13489
14
central and distributed CSIRTs, the coordinating team model is
not addressed in detail in this
document.
16
Incident response teams can also use any of three staffing
models:
response work, with limited technical and

administrative support from contractors.
ganization outsources portions of
its incident response work.
Section 2.4.2 discusses the major factors that should be
considered with outsourcing. Although
incident response duties can be divided among the organization
and one or more outsourcers in many
ways, a few arrangements have become commonplace:
– The most prevalent arrangement is for the organization to
outsource 24-hours-a-day, 7-days-a-
week (24/7) monitoring of intrusion detection sensors, firewalls,
and other security devices to an
offsite managed security services provider (MSSP). The MSSP
identifies and analyzes suspicious
activity and reports each detected incident to the organization’s
incident response team.
– Some organizations perform basic incident response work in-
house and call on contractors to
assist with handling incidents, particularly those that are more
serious or widespread.
incident response work, typically to
an onsite contractor. This model is most likely to be used when
the organization needs a full-time,
onsite incident response team but does not have enough
available, qualified employees. It is assumed

that the organization will have employees supervising and
overseeing the outsourcer’s work.
2.4.2 Team Model Selection
When selecting appropriate structure and staffing models for an
incident response team, organizations
should consider the following factors:
incident response staff to be available 24/7.
This typically means that incident handlers can be contacted by
phone, but it can also mean that an
onsite presence is required. Real-time availability is the best for
incident response because the longer
an incident lasts, the more potential there is for damage and
loss. Real-time contact is often needed
when working with other organizations—for example, tracing an
attack back to its source.
-Time Versus Part-Time Team Members. Organizations
with limited funding, staffing, or
incident response needs may have only part-time incident
response team members, serving as more of
a virtual incident response team. In this case, the incident
response team can be thought of as a
volunteer fire department. When an emergenc y occurs, the team
members are contacted rapidly, and
those who can assist do so. An existing group such as the IT

help desk can act as a first POC for
incident reporting. The help desk members can be trained to
perform the initial investigation and data
gathering and then alert the incident response team if it appears
that a serious incident has occurred.
as are the on-call responsibilities of most
team members. This combination makes it easy for incident
response team members to become
overly stressed. Many organizations will also struggle to find
willing, available, experienced, and
properly skilled people to participate, particularly in 24-hour
support. Segregating roles, particularly
16
Information about the Coordinating team model, as well as
extensive information on other team models, is available in a
CERT
®
/CC document titled Organizational Models for Computer
Security Incident Response Teams (CSIRTs)
(http://www.cert.org/archive/pdf/03hb001.pdf).
http://www.cert.org/archive/pdf/03hb001.pdf

15
reducing the amount of administrative work that team members
are responsible for performing, can
be a significant boost to morale.
required to be onsite 24/7. Organizations
may fail to include incident response-specific costs in budgets,
such as sufficient funding for training
and maintaining skills. Because the incident response team
works with so many facets of IT, its
members need much broader knowledge than most IT staff
members. They must also understand how
to use the tools of incident response, such as digital forensics
software. Other costs that may be
overlooked are physical security for the team’s work areas and
communications mechanisms.
knowledge and experience in several
technical areas; the breadth and depth of knowledge required
varies based on the severity of the
organization’s risks. Outsourcers may possess deeper
knowledge of intrusion detection, forensics,
vulnerabilities, exploits, and other aspects of security than
employees of the organization. Also,

MSSPs may be able to correlate events among customers so that
they can identify new threats more
quickly than any individual customer could. However, technical
staff members within the
organization usually have much better knowledge of the
organization’s environment than an
outsourcer would, which can be beneficial in identifying false
positives associated with organization-
specific behavior and the criticality of targets. Section 2.4.3
contains additional information on
recommended team member skills.
When considering outsourcing, organizations should keep these
issues in mind:
consider not only the current quality
(breadth and depth) of the outsourcer’s work, but also efforts to
ensure the quality of future work—
for example, minimizing turnover and burnout and providing a
solid training program for new
employees. Organizations should think about how they could
objectively assess the quality of the
outsourcer’s work.
unwilling to give an outsourcer authority to

make operational decisions for the environment (e.g.,
disconnecting a web server). It is important to
document the appropriate actions for these decision points. For
example, one partially outsourced
model addresses this issue by having the outsourcer provide
incident data to the organization’s
internal team, along with recommendations for further handling
the incident. The internal team
ultimately makes the operational decisions, with the outsourcer
continuing to provide support as
needed.
incident response responsibilities and
restricting access to sensitive information can limit this. For
example, a contractor may determine
what user ID was used in an incident (e.g., ID 123456) but not
know what person is associated with
the user ID. Employees can then take over the investigation.
Non-disclosure agreements (NDAs) are
one possible option for protecting the disclosure of sensitive
information.
-Specific Knowledge. Accurate analysis
and prioritization of incidents are
dependent on specific knowledge of the organization’s
environment. The organization should provide

the outsourcer regularly updated documents that define what
incidents it is concerned about, which
resources are critical, and what the level of response should be
under various sets of circumstances.
The organization should also report all changes and updates
made to its IT infrastructure, network
configuration, and systems. Otherwise, the contractor has to
make a best guess as to how each
incident should be handled, inevitably leading to mishandled
incidents and frustration on both sides.
Lack of organization-specific knowledge can also be a problem
when incident response is not
outsourced if communications are weak among teams or if the
organization simply does not collect
the necessary information.
16
is very important. If the intrusion
detection system records an attempted attack against a web
server, but the outsourcer has no access to
the server’s logs, it may be unable to determine whether the
attack was successful. To be efficient, the

outsourcer will require administrative privileges to critical
systems and security device logs remotely
over a secure channel. This will increase administration costs,
introduce additional access entry
points, and increase the risk of unauthorized disclosure of
sensitive information.
response work often requires a
physical presence at the organization’s facilities. If the
outsourcer is offsite, consider where the
outsourcer is located, how quickly it can have an incident
response team at any facility, and how
much this will cost. Consider onsite visits; perhaps there are
certain facilities or areas where the
outsourcer should not be permitted to work.
-House.
Organizations that completely outsource incident
response should strive to maintain basic incident response skills
in-house. Situations may arise in
which the outsourcer is unavailable, so the organization should
be prepared to perform its own
incident handling. The organization’s technical staff must also
be able to understand the significance,
technical implications, and impact of the outsourcer’s
recommendations.

2.4.3 Incident Response Personnel
A single employee, with one or more designated alternates,
should be in charge of incident response. In a
fully outsourced model, this person oversees and evaluates the
outsourcer’s work. All other models
generally have a team manager and one or more deputies who
assumes authority in the absence of the
team manager. The managers typically perform a variety of
tasks, including acting as a liaison with upper
management and other teams and organizations, defusing crisis
situations, and ensuring that the team has
the necessary personnel, resources, and skills. Managers should
be technically adept and have excellent
communication skills, particularly an ability to communicate to
a range of audiences. Managers are
ultimately responsible for ensuring that incident response
activities are performed properly.
In addition to the team manager and deputy, some teams also
have a technical lead—a person with strong
technical skills and incident response experience who assumes
oversight of and final responsibility for the
quality of the team’s technical work. The position of technical
lead should not be confused with the

position of incident lead. Larger teams often assign an incident
lead as the primary POC for handling a
specific incident; the incident lead is held accountable for the
incident’s handling. Depending on the size
of the incident response team and the magnitude of the incident,
the incident lead may not actually
perform any actual incident handling, but rather coordinate the
handlers’ activities, gather information
from the handlers, provide incident updates to other groups, and
ensure that the team’s needs are met.
Members of the incident response team should have excellent
technical skills, such as system
administration, network administration, programming, technical
support, or intrusion detection. Every
team member should have good problem solving skills and
critical thinking abilities. It is not necessary
for every team member to be a technical expert—to a large
degree, practical and funding considerations
will dictate this—but having at least one highly proficient
person in each major area of technology (e.g.,
commonly attacked operating systems and applications) is a
necessity. It may also be helpful to have
some team members specialize in particular technical areas,
such as network intrusion detection, malware

analysis, or forensics. It is also often helpful to temporarily
bring in technical specialists that aren’t
normally part of the team.
It is important to counteract staff burnout by providing
opportunities for learning and growth. Suggestions
for building and maintaining skills are as follows:
17
proficiency in technical areas and security
disciplines, as well as less technical topics such as the legal
aspects of incident response. This should
include sending staff to conferences and encouraging or
otherwise incentivizing participation in
conferences, ensuring the availability of technical references
that promote deeper technical
understanding, and occasionally bringing in outside experts
(e.g., contractors) with deep technical
knowledge in needed areas as funding permits.
such as creating educational materials,
conducting security awareness workshops, and performing
research.

in and out of the incident
response team, and participate in
exchanges in which team members temporarily trade places with
others (e.g., network administrators)
to gain new technical skills.
e
uninterrupted time off work (e.g.,
vacations).
to help less experienced staff learn
incident handling.
members discuss how they would handle
them. Appendix A contains a set of scenarios and a list of
questions to be used during scenario
discussions.
Incident response team members should have other skills in
addition to technical expertise. Teamwork
skills are of fundamental importance because cooperation and
coordination are necessary for successful
incident response. Every team member should also have good
communication skills. Speaking skills are
important because the team will interact with a wide variety of
people, and writing skills are important
when team members are preparing advisories and procedures.

Although not everyone within a team needs
to have strong writing and speaking skills, at least a few people
within every team should possess them so
the team can represent itself well in front of others.
2.4.4 Dependencies within Organizations
It is important to identify other groups within the organization
that may need to participate in incident
handling so that their cooperation can be solicited before it is
needed. Every incident response team relies
on the expertise, judgment, and abilities of others, including:
policy, budget, and staffing. Ultimately,
management is held responsible for coordinating incident
response among various stakeholders,
minimizing damage, and reporting to Congress, OMB, the
General Accounting Office (GAO), and
other parties.
may be needed during certain stages of
incident handling (prevention, containment, eradication, and
recovery)—for example, to alter network
security controls (e.g., firewall rulesets).
administrators) not only have the needed

skills to assist but also usually have the best understanding of
the technology they manage on a daily
basis. This understanding can ensure that the appropriate
actions are taken for the affected system,
such as whether to disconnect an attacked system.
18
response plans, policies, and procedures to
ensure their compliance with law and Federal guidance,
including the right to privacy. In addition, the
guidance of the general counsel or legal department should be
sought if there is reason to believe that
an incident may have legal ramifications, including evidence
collection, prosecution of a suspect, or a
lawsuit, or if there may be a need for a memorandum of
understanding (MOU) or other binding
agreements involving liability limitations for information
sharing.
and impact of an incident, a need may
exist to inform the media and, by extension, the public.

incident, the human resources
department may be involved—for example, in assisting with
disciplinary proceedings.
ions should ensure
that incident response policies and
procedures and business continuity processes are in sync.
Computer security incidents undermine the
business resilience of an organization. Business continuity
planning professionals should be made
aware of incidents and their impacts so they can fine-tune
business impact assessments, risk
assessments, and continuity of operations plans. Further,
because business continuity planners have
extensive expertise in minimizing operational disruption during
severe circumstances, they may be
valuable in planning responses to certain situations, such as
denial of service (DoS) conditions.
security incidents occur through
breaches of physical security or involve coordinated logical and
physical attacks. The incident
response team also may need access to facilities during incident
handling—for example, to acquire a
compromised workstation from a locked office.
2.5 Incident Response Team Services

The main focus of an incident response team is performing
incident response, but it is fairly rare for a
team to perform incident response only. The following are
examples of other services a team might offer:
irst tier of an incident response
team often assumes responsibility for
intrusion detection.
17
The team generally benefits because it should be poised to
analyze incidents
more quickly and accurately, based on the knowledge it gains of
intrusion detection technologies.
the organization regarding new
vulnerabilities and threats.
18
Automated methods should be used whenever appropriate to
disseminate
information; for example, the National Vulnerability Database
(NVD) provides information via XML
and RSS feeds when new vulnerabilities are added to it.
19
Advisories are often most necessary when
new threats are emerging, such as a high-profile social or
political event (e.g., celebrity wedding) that

attackers are likely to leverage in their social engineering. Only
one group within the organization
should distribute computer security advisories to avoid
duplicated effort and conflicting information.
cation and awareness are
resource multipliers—the more the users
and technical staff know about detecting, reporting, and
responding to incidents, the less drain there
17
See NIST SP 800-94, Guide to Intrusion Detection and
Prevention Systems (IDPS) for more information on IDPS
technologies. It is available at
http://csrc.nist.gov/publications/PubsSPs.html#800-94.
18
Teams should word advisories so that they do not blame any
person or organization for security issues. Teams should meet
with legal advisors to discuss the possible need for a disclaimer
in advisories, stating that the team and organization has no
liability in regard to the accuracy of the advisory. This is most
pertinent when advisories may be sent to contractors,
vendors, and other nonemployees who are users of the
organization’s computing resources.
19
http://nvd.nist.gov/

http://csrc.nist.gov/publications/PubsSPs.html#800-94
19
should be on the incident response team. This information can
be communicated through many
means: workshops, websites, newsletters, posters, and even
stickers on monitors and laptops.
sponse teams often
participate in information sharing groups, such
as ISACs or regional partnerships. Accordingly, incident
response teams often manage the
organization’s incident information sharing efforts, such as
aggregating information related to
incidents and effectively sharing that information with other
organizations, as well as ensuring that
pertinent information is shared within the enterprise.
2.6 Recommendations
The key recommendations presented in this section for
organizing a computer security incident handling
capability are summarized below.
Organizations should be prepared to respond

quickly and effectively when computer security defenses are
breached. FISMA requires Federal
agencies to establish incident response capabilities.
policy is the foundation of the incident
response program. It defines which events are considered
incidents, establishes the organizatio nal
structure for incident response, defines roles and
responsibilities, and lists the requirements for
reporting incidents, among other items.
response policy. The incident response
plan provides a roadmap for implementing an incident response
program based on the organization’s
policy. The plan indicates both short- and long-term goals for
the program, including metrics for
measuring the program. The incident response plan should also
indicate how often incident handlers
should be trained and the requirements for incident handlers.
procedures provide detailed steps for
responding to an incident. The procedures should cover all the
phases of the incident response
process. The procedures should be based on the incident
response policy and plan.

-related
information sharing. The
organization should communicate appropriate incident details
with outside parties, such as the media,
law enforcement agencies, and incident reporting organizations.
The incident response team should
discuss this with the organization’s public affairs office, legal
department, and management to
establish policies and procedures regarding information sharing.
The team should comply with
existing organization policy on interacting with the media and
other outside parties.
organization. Federal civilian
agencies are required to report incidents to US-CERT; other
organizations can contact US-CERT
and/or their ISAC. Reporting is beneficial because US-CERT
and the ISACs use the reported data to
provide information to the reporting parties regarding new
threats and incident trends.
response team model. Organizations
should carefully weigh the advantages and disadvantages of
each possible team structure model and
staffing model in the context of the organization’s needs and
available resources.

team. The credibility and
proficiency of the team depend to a large extent on the technical
skills and critical thinking abilities of
its members. Critical technical skills include system
administration, network administration,
programming, technical support, and intrusion detection.
Teamwork and communications skills are
20
also needed for effective incident handling. Necessary training
should be provided to all team
members.
to participate in incident handling.
Every incident response team relies on the expertise, judgment,
and abilities of other teams, including
management, information assurance, IT support, legal, public
affairs, and facilities management.
main focus of the team is incident
response, most teams perform additional functions. Examples
include monitoring intrusion detection
sensors, distributing security advisories, and educating users on

security.
21
3. Handling an Incident
The incident response process has several phases. The initial
phase involves establishing and training an
incident response team, and acquiring the necessary tools and
resources. During preparation, the
organization also attempts to limit the number of incidents that
will occur by selecting and implementing
a set of controls based on the results of risk assessments.
However, residual risk will inevitably persist
after controls are implemented. Detection of security breaches
is thus necessary to alert the organization
whenever incidents occur. In keeping with the severity of the
incident, the organization can mitigate the
impact of the incident by containing it and ultimately
recovering from it. During this phase, activity often
cycles back to detection and analysis—for example, to see if
additional hosts are infected by malware
while eradicating a malware incident. After the incident is
adequately handled, the organization issues a

report that details the cause and cost of the incident and the
steps the organization should take to prevent
future incidents. This section describes the major phases of the
incident response process—preparation,
detection and analysis, containment, eradication and recovery,
and post-incident activity—in detail.
Figure 3-1 illustrates the incident response life cycle.
Figure 3-1. Incident Response Life Cycle
3.1 Preparation
Incident response methodologies typically emphasize
preparation—not only establishing an incident
response capability so that the organization is ready to respond
to incidents, but also preventing incidents
by ensuring that systems, networks, and applications are
sufficiently secure. Although the incident
response team is not typically responsible for incident
prevention, it is fundamental to the success of
incident response programs. This section provides basic advice
on preparing to handle incidents and on
preventing incidents.
3.1.1 Preparing to Handle Incidents
The lists below provide examples of tools and resources

available that may be of value during incident
handling. These lists are intended to be a starting point for
discussions about which tools and resources an
organization’s incident handlers need. For example,
smartphones are one way to have resilient emergency
22
communication and coordination mechanisms. An organization
should have multiple (separate and
different) communication and coordination mechanisms in case
of failure of one mechanism.
Incident Handler Communications and Facilities:
outside the organization (primary and
backup contacts), such as law enforcement and other incident
response teams; information may
include phone numbers, email addresses, public encryption keys
(in accordance with the encryption
software described below), and instructions for verifying the
contact’s identity
-call information for other teams within the organization,
including escalation information

addresses, online forms, and secure
instant messaging systems that users can use to report suspected
incidents; at least one mechanism
should permit people to report incidents anonymously
status, etc.
-hour
support and onsite communications
team members, within the organization
and with external parties; for Federal agencies, software must
use a FIPS-validated encryption
algorithm
20
permanent war room is not necessary or
practical, the team should create a procedure for procuring a
temporary war room when needed
sensitive materials
Incident Analysis Hardware and Software:
21
and/or backup devices to create disk images, preserve log files,

and
save other relevant incident data
packets, and writing reports
the virtualized equivalents, which
may be used for many purposes, such as restoring backups and
trying out malware
from non-networked systems
l analyzers to capture and analyze
network traffic
used to gather evidence from systems
-bound
notebooks, digital cameras, audio recorders,
chain of custody forms, evidence storage bags and tags, and
evidence tape, to preserve evidence for
possible legal actions
20
FIPS 140-2, Security Requirements for Cryptographic

Modules, http://csrc.nist.gov/publications/PubsFIPS.html.
21
A digital forensic workstation is specially designed to assist
incident handlers in acquiring and analyzing data. These
workstations typically contain a set of removable hard drives
that can be used for evidence storage.
23
Incident Analysis Resources:
ports
detection and antivirus products
database servers
application activity
22
to speed incident analysis, verification, and eradication
Incident Mitigation Software:

for restoration and recovery purposes
Many incident response teams create a jump kit, which is a
portable case that contains materials that may
be needed during an investigation. The jump kit should be ready
to go at all times. Jump kits contain
many of the same items listed in the bulleted lists above. For
example, each jump kit typically includes a
laptop, loaded with appropriate software (e.g., packet sniffers,
digital forensics). Other important
materials include backup devices, blank media, and basic
networking equipment and cables. Because the
purpose of having a jump kit is to facilitate faster responses, the
team should avoid borrowing items from
the jump kit.
Each incident handler should have access to at least two
computing devices (e.g., laptops). One, such as
the one from the jump kit, should be used to perform packet
sniffing, malware analysis, and all other
actions that risk contaminating the laptop that performs them.
This laptop should be scrubbed and all
software reinstalled before it is used for another incident. Note
that because this laptop is special purpose,

it is likely to use software other than the standard enterprise
tools and configurations, and whenever
possible the incident handlers should be allowed to specify
basic technical requirements for these special-
purpose investigative laptops. In addition to an investigative
laptop, each incident handler should also
have a standard laptop, smart phone, or other computing device
for writing reports, reading email, and
performing other duties unrelated to the hands-on incident
analysis.
Exercises involving simulated incidents can also be very useful
for preparing staff for incident handling;
see NIST SP 800-84 for more information on exercises
23
and Appendix A for sample exercise scenarios.
3.1.2 Preventing Incidents
Keeping the number of incidents reasonably low is very
important to protect the business processes of the
organization. If security controls are insufficient, higher
volumes of incidents may occur, overwhelming
the incident response team. This can lead to slow and
incomplete responses, which translate to a larger
negative business impact (e.g., more extensive damage, longer
periods of service and data unavailability).

It is outside the scope of this document to provide specific
advice on securing networks, systems, and
applications. Although incident response teams are generally
not responsible for securing resources, they
can be advocates of sound security practices. An incident
response team may be able to identify problems
that the organization is otherwise not aware of; the team can
play a key role in risk assessment and
training by identifying gaps. Other documents already provide
advice on general security concepts and
22
The National Software Reference Library (NSRL) Project
maintains records of hashes of various files, including operating
system, application, and graphic image files. The hashes can be
downloaded from http://www.nsrl.nist.gov/.
23
Guide to Test, Training, and Exercise Programs for IT Plans
and Capabilities,
http://www.nsrl.nist.gov/

24
operating system and application-specific guidelines.
24
The following text, however, provides a brief
overview of some of the main recommended practices for
securing networks, systems, and applications:
ments of systems and
applications should determine what
risks are posed by combinations of threats and vulnerabilities.
25
This should include understanding the
applicable threats, including organization-specific threats. Each
risk should be prioritized, and the
risks can be mitigated, transferred, or accepted until a
reasonable overall level of risk is reached.
Another benefit of conducting risk assessments regularly is that
critical resources are identified,
allowing staff to emphasize monitori ng and response activities
for those resources.
26
using standard configurations. In addition
to keeping each host properly patched, hosts should be
configured to follow the principle of least

privilege—granting users only the privileges necessary for
performing their authorized tasks. Hosts
should have auditing enabled and should log significant
security-related events. The security of hosts
and their configurations should be continuously monitored.
27
Many organizations use Security
Content Automation Protocol (SCAP)
28
expressed operating system and application configuration
checklists to assist in securing hosts consistently and
effectively.
29
perimeter should be
configured to deny all activity that is not
expressly permitted. This includes securing all connection
points, such as virtual private networks
(VPNs) and dedicated connections to other organizations.
to detect and stop malware
should be deployed throughout the
organization. Malware protection should be deployed at the host
level (e.g., server and workstation
operating systems), the application server level (e.g., email
server, web proxies), and the application

client level (e.g., email clients, instant messaging clients).
30
policies and procedures regarding
appropriate use of networks, systems, and applications.
Applicable lessons learned from previous
incidents should also be shared with users so they can see how
their actions could affect the
organization. Improving user awareness regarding incidents
should reduce the frequency of incidents.
IT staff should be trained so that they can maintain their
networks, systems, and applications in
accordance with the organization’s security standards.
24
http://csrc.nist.gov/publications/PubsSPs.html provides links
to the NIST Special Publications on computer security, which
include documents on operating system and application security
baselines.
25
Guidelines on risk assessment are available in NIST SP 800-
30, Guide for Conducting Risk Assessments, at
http://csrc.nist.gov/publications/PubsSPs.html#800-30-Rev1.
26

Information on identifying critical resources is discussed in
FIPS 199, Standards for Security Categorization of Federal
Information and Information Systems, at
http://csrc.nist.gov/publications/PubsFIPS.html.
27
For more information on continuous monitoring, see NIST SP
800-137, Information Security Continuous Monitoring for
Federal Information Systems and Organizations
(http://csrc.nist.gov/publications/PubsSPs.html#800-137).
28
More information on SCAP is available from NIST SP 800-117
Revision 1, Guide to Adopting and Using the Security
Content Automation Protocol (SCAP) Version 1.2
(http://csrc.nist.gov/publications/PubsSPs.html#800-117).
29
NIST hosts a security checklists repository at
http://checklists.nist.gov/.
30
More information on malware prevention is available from
NIST SP 800-83, Guide to Malware Incident Prevention and
Handling (http://csrc.nist.gov/publications/PubsSPs.html#800-
83).
http://csrc.nist.gov/publications/PubsSPs.html
http://www.cisecurity.org/
http://www.cisecurity.org/
http://csrc.nist.gov/publications/PubsSPs.html#800-30-Rev1

http://checklists.nist.gov/
25
3.2 Detection and Analysis
Figure 3-2. Incident Response Life Cycle (Detection and
Analysis)
3.2.1 Attack Vectors
Incidents can occur in countless ways, so it is infeasible to
develop step-by-step instructions for handling
every incident. Organizations should be generally prepared to
handle any incident but should focus on
being prepared to handle incidents that use common attack
vectors. Different types of incidents merit
different response strategies. The attack vectors listed below are
not intended to provide definitive
classification for incidents; rather, they simply list common
methods of attack, which can be used as a
basis for defining more specific handling procedures.

removable media or a peripheral device—for
example, malicious code spreading onto a system from an
infected USB flash drive.
compromise, degrade, or destroy systems,
networks, or services (e.g., a DDoS intended to impair or deny
access to a service or application; a
brute force attack against an authentication mechanism, such as
passwords, CAPTCHAS, or digital
signatures).
-based
application—for example, a cross-site
scripting attack used to steal credentials or a redirect to a site
that exploits a browser vulnerability and
installs malware.
attachment—for example, exploit code disguised
as an attached document or a link to a malicious website in the
body of an email message.
ersonation: An attack involving replacement of something
benign with something malicious—
for example, spoofing, man in the middle attacks, rogue
wireless access points, and SQL injection
attacks all involve impersonation.
t resulting from violation of an
organization’s acceptable usage

policies by an authorized user, excluding the above categories;
for example, a user installs file sharing
software, leading to the loss of sensitive data; or a user
performs illegal activities on a system.
26
device or media used by the
organization, such as a laptop, smartphone, or authentication
token.
t does not fit into any of the other
categories.
This section focuses on recommended practices for handling any
type of incident. It is outside the scope
of this publication to give specific advice based on the attack
vectors; such guidelines would be provided
in separate publications addressing other incident handling
topics, such as NIST SP 800-83 on malware
incident prevention and handling.
3.2.2 Signs of an Incident
For many organizations, the most challenging part of the
incident response process is accurately detecting

and assessing possible incidents—determining whether an
incident has occurred and, if so, the type,
extent, and magnitude of the problem. What makes this so
challenging is a combination of three factors:
be detected through many different means,
with varying levels of detail and fidelity.
Automated detection capabilities include network-based and
host-based IDPSs, antivirus software,
and log analyzers. Incidents may also be detected through
manual means, such as problems reported
by users. Some incidents have overt signs that can be easily
detected, whereas others are almost
impossible to detect.
—
for example, it is not uncommon for an
organization to receive thousands or even millions of intrusion
detection sensor alerts per day. (See
Section 3.2.4 for information on analyzing such alerts.)
experience are necessary for proper and
efficient analysis of incident-related data.
Signs of an incident fall into one of two categories: precursors
and indicators. A precursor is a sign that
an incident may occur in the future. An indicator is a sign that
an incident may have occurred or may be

occurring now.
Most attacks do not have any identifiable or detectable
precursors from the target’s perspective. If
precursors are detected, the organization may have an
opportunity to prevent the incident by altering its
security posture to save a target from attack. At a minimum, the
organization could monitor activity
involving the target more closely. Examples of precursors are:
scanner
ploit that targets a vulnerability
of the organization’s mail server
organization.
While precursors are relatively rare, indicators are all too
common. Too many types of indicators exist to
exhaustively list them, but some examples are listed below:
overflow attempt occurs against a database
server.
infected with malware.
characters.

27
unfamiliar remote system.
emails with suspicious content.
typical network traffic flows.
3.2.3 Sources of Precursors and Indicators
Precursors and indicators are identified using many different
sources, with the most common being
computer security software alerts, logs, publicly available
information, and people. Table 3-2 lists
common sources of precursors and indicators for each category.
Table 3-1. Common Sources of Precursors and Indicators
Source Description
Alerts
IDPSs IDPS products identify suspicious events and record
pertinent data regarding them, including the

date and time the attack was detected, the type of attack, the
source and destination IP
addresses, and the username (if applicable and known). Most
IDPS products use attack
signatures to identify malicious activity; the signatures must be
kept up to date so that the
newest attacks can be detected. IDPS software often produces
false positives—alerts that
indicate malicious activity is occurring, when in fact there has
been none. Analysts should
manually validate IDPS alerts either by closely reviewing the
recorded supporting data or by
getting related data from other sources.
31
SIEMs Security Information and Event Management (SIEM)
products are similar to IDPS products, but
they generate alerts based on analysis of log data (see below).
Antivirus and
antispam
software
Antivirus software detects various forms of malware, generates
alerts, and prevents the malware
from infecting hosts. Current antivirus products are effective at
stopping many instances of
malware if their signatures are kept up to date. Antispam
software is used to detect spam and
prevent it from reaching users’ mailboxes. Spam may contain
malware, phishing attacks, and
other malicious content, so alerts from antispam software may
indicate attack attempts.

File integrity
checking
software
File integrity checking software can detect changes made to
important files during incidents. It
uses a hashing algorithm to obtain a cryptographic checksum for
each designated file. If the file
is altered and the checksum is recalculated, an extremely high
probability exists that the new
checksum will not match the old checksum. By regularly
recalculating checksums and comparing
them with previous values, changes to files can be detected.
Third-party
monitoring
services
Third parties offer a variety of subscription-based and free
monitoring services. An example is
fraud detection services that will notify an organization if its IP
addresses, domain names, etc.
are associated with current incident activity involving other
organizations. There are also free
real-time blacklists with similar information. Another example
of a third-party monitoring service
is a CSIRC notification list; these lists are often available only
to other incident response teams.
Logs
Operating
system,
service and
application

logs
Logs from operating systems, services, and applications
(particularly audit-related data) are
frequently of great value when an incident occurs, such as
recording which accounts were
accessed and what actions were performed. Organizations
should require a baseline level of
logging on all systems and a higher baseline level on critical
systems. Logs can be used for
analysis by correlating event information. Depending on the
event information, an alert can be
generated to indicate an incident. Section 3.2.4 discusses the
value of centralized logging.
Network
device logs
Logs from network devices such as firewalls and routers are not
typically a primary source of
precursors or indicators. Although these devices are usually
configured to log blocked
connection attempts, they provide little information about the
nature of the activity. Still, they can
be valuable in identifying network trends and in correlating
events detected by other devices.
31
See NIST SP 800-94, Guide to Intrusion Detection and
Prevention Systems, for additional information on IDPS
products. It
is available at

28
Source Description
Network flows A network flow is a particular communication
session occurring between hosts. Routers and
other networking devices can provide network flow information,
which can be used to find
anomalous network activity caused by malware, data
exfiltration, and other malicious acts. There
are many standards for flow data formats, including NetFlow,
sFlow, and IPFIX.
Publicly Available Information
Information on
new
vulnerabilities
and exploits
Keeping up with new vulnerabilities and exploits can prevent
some incidents from occurring and
assist in detecting and analyzing new attacks. The National
Vulnerability Database (NVD)
contains information on vulnerabilities.
32
Organizations such as US-CERT
33

and CERT
®
/CC
periodically provide threat update information through
briefings, web postings, and mailing lists.
People
People from
within the
organization
Users, system administrators, network administrators, security
staff, and others from within the
organization may report signs of incidents. It is important to
validate all such reports. One
approach is to ask people who provide such information how
confident they are of the accuracy
of the information. Recording this estimate along with the
information provided can help
considerably during incident analysis, particularly when
conflicting data is discovered.
People from
other
organizations
Reports of incidents that originate externally should be taken
seriously. For example, the
organization might be contacted by a party claiming a system at
the organization is attacking its
systems. External users may also report other indicators, such as
a defaced web page or an
unavailable service. Other incident response teams also may

report incidents. It is important to
have mechanisms in place for external parties to report
indicators and for trained staff to monitor
those mechanisms carefully; this may be as simple as setting up
a phone number and email
address, configured to forward messages to the help desk.
3.2.4 Incident Analysis
Incident detection and analysis would be easy if every precursor
or indicator were guaranteed to be
accurate; unfortunately, this is not the case. For example, user -
provided indicators such as a complaint of
a server being unavailable are often incorrect. Intrusion
detection systems may produce false positives—
incorrect indicators. These examples demonstrate what makes
incident detection and analysis so difficult:
each indicator ideally should be evaluated to determine if it is
legitimate. Making matters worse, the total
number of indicators may be thousands or millions a day.
Finding the real security incidents that occurred
out of all the indicators can be a daunting task.
Even if an indicator is accurate, it does not necessarily mean
that an incident has occurred. Some
indicators, such as a server crash or modification of critical
files, could happen for several reasons other

than a security incident, including human error. Given the
occurrence of indicators, however, it is
reasonable to suspect that an incident might be occurring and to
act accordingly. Determining whether a
particular event is actually an incident is sometimes a matter of
judgment. It may be necessary to
collaborate with other technical and information security
personnel to make a decision. In many instances,
a situation should be handled the same way regardless of
whether it is security related. For example, if an
organization is losing Internet connectivity every 12 hours and
no one knows the cause, the staff would
want to resolve the problem just as quickly and would use the
same resources to diagnose the problem,
regardless of its cause.
Some incidents are easy to detect, such as an obviously defaced
web page. However, many incidents are
not associated with such clear symptoms. Small signs such as
one change in one system configuration file
may be the only indicators that an incident has occurred. In
incident handling, detection may be the most
difficult task. Incident handlers are responsible for analyzing
ambiguous, contradictory, and incomplete
symptoms to determine what has happened. Although technical

solutions exist that can make detection
32
33
http://www.us-cert.gov/cas/signup.html
http://www.us-cert.gov/cas/signup.html
29
easier, the best remedy is to build a team of highly experienced
and proficient staff members who can
analyze the precursors and indicators effectively and efficiently
and take appropriate actions. Without a
well-trained and capable staff, incident detection and analysis
will be conducted inefficiently, and costly
mistakes will be made.
The incident response team should work quickly to analyze and
validate each incident, following a pre-
defined process and documenting each step taken. When the
team believes that an incident has occurred,
the team should rapidly perform an initial analysis to determine

the incident’s scope, such as which
networks, systems, or applications are affected; who or what
originated the incident; and how the incident
is occurring (e.g., what tools or attack methods are being used,
what vulnerabilities are being exploited).
The initial analysis should provide enough information for the
team to prioritize subsequent activities,
such as containment of the incident and deeper analysis of the
effects of the incident.
Performing the initial analysis and validation is challenging.
The following are recommendations for
making incident analysis easier and more effective:
characteristics of expected activity so that
changes to it can be more easily identified. Examples of
profiling are running file integrity checking
software on hosts to derive checksums for critical files and
monitoring network bandwidth usage to
determine what the average and peak usage levels are on various
days and times. In practice, it is
difficult to detect incidents accurately using most profiling
techniques; organizations should use
profiling as one of several detection and analysis techniques.
s. Incident response team

members should study networks, systems,
and applications to understand what their normal behavior is so
that abnormal behavior can be
recognized more easily. No incident handler will have a
comprehensive knowledge of all behavior
throughout the environment, but handlers should know which
experts could fill in the gaps. One way
to gain this knowledge is through reviewing log entries and
security alerts. This may be tedious if
filtering is not used to condense the logs to a reasonable size.
As handlers become more familiar with
the logs and alerts, they should be able to focus on unexplained
entries, which are usually more
important to investigate. Conducting frequent log reviews
should keep the knowledge fresh, and the
analyst should be able to notice trends and changes over time.
The reviews also give the analyst an
indication of the reliability of each source.
incident may be recorded in several places,
such as firewall, IDPS, and application logs. Creating and
implementing a log retention policy that
specifies how long log data should be maintained may be
extremely helpful in analysis because older
log entries may show reconnaissance activity or previous

instances of similar attacks. Another reason
for retaining logs is that incidents may not be discovered until
days, weeks, or even months later. The
length of time to maintain log data is dependent on several
factors, including the organization’s data
retention policies and the volume of data. See NIST SP 800-92,
Guide to Computer Security Log
Management for additional recommendations related to logging.
34
captured in several logs that each
contain different types of data—a firewall log may have the
source IP address that was used, whereas
an application log may contain a username. A network IDPS
may detect that an attack was launched
against a particular host, but it may not know if the attack was
successful. The analyst may need to
examine the host’s logs to determine that information.
Correlating events among multiple indicator
sources can be invaluable in validating whether a particular
incident occurred.
34

30
uch as the
Network Time Protocol (NTP)
synchronize clocks among hosts.
35
Event correlation will be more complicated if the devices
reporting
events have inconsistent clock settings. From an evidentiary
standpoint, it is preferable to have
consistent timestamps in logs—for example, to have three logs
that show an attack occurred at
12:07:01 a.m., rather than logs that list the attack as occurring
at 12:07:01, 12:10:35, and 11:07:06.
knowledge base should include
information that handlers need for referencing quickly during
incident analysis. Although it is
possible to build a knowledge base with a complex structure, a
simple approach can be effective. Text
documents, spreadsheets, and relatively simple databases
provide effective, flexible, and searchable

mechanisms for sharing data among team members. The
knowledge base should also contain a
variety of information, including explanations of the
significance and validity of precursors and
indicators, such as IDPS alerts, operating system log entries,
and application error codes.
engines can help analysts find
information on unusual activity. For example, an analyst may
see some unusual connection attempts
targeting TCP port 22912. Performing a search on the terms
“TCP,” “port,” and “22912” may return
some hits that contain logs of similar activity or even an
explanation of the significance of the port
number. Note that separate workstations should be used for
research to minimize the risk to the
organization from conducting these searches.
the indicators do not record enough
detail to permit the handler to understand what is occurring. If
an incident is occurring over a
network, the fastest way to collect the necessary data may be to
have a packet sniffer capture network
traffic. Configuring the sniffer to record traffic that matches
specified criteria should keep the volume

of data manageable and minimize the inadvertent capture of
other information. Because of privacy
concerns, some organizations may require incident handlers to
request and receive permission before
using packet sniffers.
Filter the Data. There is simply not enough time to review
and analyze all the indicators; at
minimum the most suspicious activity should be investigated.
One effective strategy is to filter out
categories of indicators that tend to be insignificant. Another
filtering strategy is to show only the
categories of indicators that are of the highest significance;
however, this approach carries substantial
risk because new malicious activity may not fall into one of the
chosen indicator categories.
ek Assistance from Others. Occasionally, the team will be
unable to determine the full cause and
nature of an incident. If the team lacks sufficient information to
contain and eradicate the incident,
then it should consult with internal resources (e.g., information
security staff) and external resources
(e.g., US-CERT, other CSIRTs, contractors with incident
response expertise). It is important to
accurately determine the cause of each incident so that it can be
fully contained and the exploited

vulnerabilities can be mitigated to prevent similar incidents
from occurring.
3.2.5 Incident Documentation
An incident response team that suspects that an incident has
occurred should immediately start recording
all facts regarding the incident.
36
A logbook is an effective and simple medium for this,
37
but laptops,
35
More information on NTP is available at http://www.ntp.org/.
36
Incident handlers should log only the facts regarding the
incident, not personal opinions or conclusions. Subjective
material
should be presented in incident reports, not recorded as
evidence.
37
If a logbook is used, it is preferable that the logbook is bound
and that the incident handlers number the pages, write in ink,
and leave the logbook intact (i.e., do not rip out any pages).
http://www.ntp.org/

31
audio recorders, and digital cameras can also serve this purpose.
38
Documenting system events,
conversations, and observed changes in files can lead to a more
efficient, more systematic, and less error-
prone handling of the problem. Every step taken from the time
the incident was detected to its final
resolution should be documented and timestamped. Every
document regarding the incident should be
dated and signed by the incident handler. Information of this
nature can also be used as evidence in a
court of law if legal prosecution is pursued. Whenever possible,
handlers should work in teams of at least
two: one person can record and log events while the other
person performs the technical tasks. Section
3.3.2 presents more information about evidence.
39
The incident response team should maintain records about the
status of incidents, along with other

pertinent information.
40
Using an application or a database, such as an issue tracking
system, helps ensure
that incidents are handled and resolved in a timely manner. The
issue tracking system should contain
information on the following:
forwarded for investigation, resolved, etc.)
nt handlers on this incident
owners, system administrators)
ent investigation
application).
41

The incident response team should safeguard incident data and
restrict access to it because it often
contains sensitive information—for example, data on exploited
vulnerabilities, recent security breaches,
and users that may have performed inappropriate actions. For
example, only authorized personnel should
have access to the incident database. Incident communications
(e.g., emails) and documents should be
encrypted or otherwise protected so that only authorized
personnel can read them.
38
Consider the admissibility of evidence collected with a device
before using it. For example, any devices that are potential
sources of evidence should not themselves be used to record
other evidence.
39
NIST SP 800-86, Guide to Integrating Forensic Techniques
Into Incident Response, provides detailed information on
establishing a forensic capability, including the development of
policies and procedures.
40
Appendix B contains a suggested list of data elements to
collect when incidents are reported. Also, the CERT

®
/CC
document State of the Practice of Computer Security Incident
Response Teams (CSIRTs) provides several sample incident
reporting forms. The document is available at
http://www.cert.org/archive/pdf/03tr001.pdf.
41
The Trans-European Research and Education Networking
Association (TERENA) has developed RFC 3067, TERENA's
Incident Object Description and Exchange Format Requirements
(http://www.ietf.org/rfc/rfc3067.txt). The document
provides recommendations for what information should be
collected for each incident. The IETF Extended Incident
Handling (inch) Working Group
(http://www.cert.org/ietf/inch/inch.html) created an RFC that
expands on TERENA’s
work—RFC 5070, Incident Object Description Exchange Format
(http://www.ietf.org/rfc/rfc5070.txt).
http://www.cert.org/archive/pdf/03tr001.pdf
http://www.ietf.org/rfc/rfc3067.txt
http://www.cert.org/ietf/inch/inch.html
32

3.2.6 Incident Prioritization
Prioritizing the handling of the incident is perhaps the most
critical decision point in the incident handling
process. Incidents should not be handled on a first-come, first-
served basis as a result of resource
limitations. Instead, handling should be prioritized based on the
relevant factors, such as the following:
systems typically impact the business
functionality that those systems provide, resulting in some type
of negative impact to the users of
those systems. Incident handlers should consider how the
incident will impact the existing
functionality of the affected systems. Incident handlers should
consider not only the current
functional impact of the incident, but also the likely future
functional impact of the incident if it is not
immediately contained.
confidentiality, integrity, and
availability of the organization’s information. For example, a
malicious agent may exfiltrate sensitive
information. Incident handlers should consider how this
information exfiltration will impact the

organization’s overall mission. An incident that results in the
exfiltration of sensitive information may
also affect other organizations if any of the data pertained to a
partner organization.
the type of resources it affects will
determine the amount of time and resources that must be spent
on recovering from that incident. In
some instances it is not possible to recover from an incident
(e.g., if the confidentiality of sensitive
information has been compromised) and it would not make
sense to spend limited resources on an
elongated incident handling cycle, unless that effort was
directed at ensuring that a similar incident
did not occur in the future. In other cases, an incident may
require far more resources to handle than
what an organization has available. Incident handlers should
consider the effort necessary to actually
recover from an incident and carefully weigh that against the
value the recovery effort will create and
any requirements related to incident handling.
Combining the functional impact to the organization’s systems
and the impact to the organization’s
information determines the business impact of the incident—for
example, a distributed denial of service

attack against a public web server may temporarily reduce the
functionality for users attempting to access
the server, whereas unauthorized root-level access to a public
web server may result in the exfiltration of
personally identifiable information (PII), which could have a
long-lasting impact on the organization’s
reputation.
The recoverability from the incident determines the possible
responses that the team may take when
handling the incident. An incident with a high functional impact
and low effort to recover from is an ideal
candidate for immediate action from the team. However, some
incidents may not have smooth recovery
paths and may need to be queued for a more strategic-level
response—for example, an incident that
results in an attacker exfiltrating and publicly posting gigabytes
of sensitive data has no easy recovery
path since the data is already exposed; in this case the team may
transfer part of the responsibility for
handling the data exfiltration incident to a more strategic-level
team that develops strategy for preventing
future breaches and creates an outreach plan for alerting those
individuals or organizations whose data

was exfiltrated. The team should prioritize the response to each
incident based on its estimate of the
business impact caused by the incident and the estimated efforts
required to recover from the incident.
An organization can best quantify the effect of its own incidents
because of its situational awareness.
Table 3-2 provides examples of functional impact categories
that an organization might use for rating its
own incidents. Rating incidents can be helpful in prioritizing
limited resources.
33
Table 3-2. Functional Impact Categories
Category Definition
None No effect to the organization’s ability to provide all
services to all users
Low Minimal effect; the organization can still provide all
critical services to all users but has lost
efficiency
Medium Organization has lost the ability to provide a critical
service to a subset of system users
High Organization is no longer able to provide some critical

services to any users
Table 3-3 provides examples of possible information impact
categories that describe the extent of
information compromise that occurred during the incident. In
this table, with the exception of the ‘None’
value, the categories are not mutually exclusive and the
organization could choose more than one.
Table 3-3. Information Impact Categories
Category Definition
None No information was exfiltrated, changed, deleted, or
otherwise compromised
Privacy
Breach
Sensitive personally identifiable information (PII) of taxpayer s,
employees, beneficiaries, etc.
was accessed or exfiltrated
Proprietary
Breach
Unclassified proprietary information, such as protected critical
infrastructure information (PCII),
was accessed or exfiltrated
Integrity
Loss

Sensitive or proprietary information was changed or deleted
Table 3-4 shows examples of recoverability effort categories
that reflect the level of and type of resources
required to recover from the incident.
Table 3-4. Recoverability Effort Categories
Category Definition
Regular Time to recovery is predictable with existing resources
Supplemented Time to recovery is predictable with additional
resources
Extended Time to recovery is unpredictable; additional
resources and outside help are needed
Not Recoverable Recovery from the incident is not possible
(e.g., sensitive data exfiltrated and posted
publicly); launch investigation
Organizations should also establish an escalation process for
those instances when the team does not
respond to an incident within the designated time. This can
happen for many reasons: for example, cell
phones may fail or people may have personal emergencies. The
escalation process should state how long
a person should wait for a response and what to do if no
response occurs. Generally, the first step is to

duplicate the initial contact. After waiting for a brief time—
perhaps 15 minutes—the caller should
escalate the incident to a higher level, such as the incident
response team manager. If that person does not
respond within a certain time, then the incident should be
escalated again to a higher level of
management. This process should be repeated until someone
responds.
3.2.7 Incident Notification
When an incident is analyzed and prioritized, the incident
response team needs to notify the appropriate
individuals so that all who need to be involved will play their
roles. Incident response policies should
34
include provisions concerning incident reporting—at a
minimum, what must be reported to whom and at
what times (e.g., initial notification, regular status updates).
The exact reporting requirements vary among
organizations, but parties that are typically notified include:

y
harassment through email)
ramifications)
-CERT (required for Federal agencies and systems
operated on behalf of the Federal government;
see Section 2.3.4.3)
During incident handling, the team may need to provide status
updates to certain parties, even in some
cases the entire organization. The team should plan and prepare
several communication methods,
including out-of-band methods (e.g., in person, paper), and
select the methods that are appropriate for a
particular incident. Possible communication methods include:

briefings)
for incident updates, and update the
greeting message to reflect the current incident status; use the
help desk’s voice mail greeting)
boards and doors, hand
out notices at all entrance points).
35
3.3 Containment, Eradication, and Recovery
Figure 3-3. Incident Response Life Cycle (Containment,
Eradication, and Recovery)
3.3.1 Choosing a Containment Strategy
Containment is important before an incident overwhelms
resources or increases damage. Most incidents
require containment, so that is an important consideration early
in the course of handling each incident.

Containment provides time for developing a tailored
remediation strategy. An essential part of
containment is decision-making (e.g., shut down a system,
disconnect it from a network, disable certain
functions). Such decisions are much easier to make if there are
predetermined strategies and procedures
for containing the incident. Organizations should define
acceptable risks in dealing with incidents and
develop strategies accordingly.
Containment strategies vary based on the type of incident. For
example, the strategy for containing an
email-borne malware infection is quite different from that of a
network-based DDoS attack. Organizations
should create separate containment strategies for each major
incident type, with criteria documented
clearly to facilitate decision-making. Criteria for determining
the appropriate strategy include:
provided to external parties)
ime and resources needed to implement the strategy

containment)
removed in four hours, temporary
workaround to be removed in two weeks, permanent solution).
In certain cases, some organizations redirect the attacker to a
sandbox (a form of containment) so that
they can monitor the attacker’s activity, usually to gather
additional evidence. The incident response team
should discuss this strategy with its legal department to
determine if it is feasible. Ways of monitoring an
36
attacker’s activity other than sandboxing should not be used; if
an organization knows that a system has
been compromised and allows the compromise to continue, it
may be liable if the attacker uses the
compromised system to attack other systems. The delayed
containment strategy is dangerous because an
attacker could escalate unauthorized access or compromise
other systems.
Another potential issue regarding containment is that some
attacks may cause additional damage when

they are contained. For example, a compromised host may run a
malicious process that pings another host
periodically. When the incident handler attempts to contain the
incident by disconnecting the
compromised host from the network, the subsequent pings will
fail. As a result of the failure, the
malicious process may overwrite or encrypt all the data on the
host’s hard drive. Handlers should not
assume that just because a host has been disconnected from the
network, further damage to the host has
been prevented.
3.3.2 Evidence Gathering and Handling
Although the primary reason for gathering evidence during an
incident is to resolve the incident, it may
also be needed for legal proceedings.
42
In such cases, it is important to clearly document how all
evidence, including compromised systems, has been preserved.
43
Evidence should be collected according
to procedures that meet all applicable laws and regulations that
have been developed from previous
discussions with legal staff and appropriate law enforcement

agencies so that any evidence can be
admissible in court.
44
In addition, evidence should be accounted for at all times;
whenever evidence is
transferred from person to person, chain of custody forms
should detail the transfer and include each
party’s signature. A detailed log should be kept for all evidence,
including the following:
fying information (e.g., the location, serial number,
model number, hostname, media access
control (MAC) addresses, and IP addresses of a computer)
collected or handled the evidence during the
investigation
evidence handling
Collecting evidence from computing resources presents some
challenges. It is generally desirable to
acquire evidence from a system of interest as soon as one
suspects that an incident may have occurred.
Many incidents cause a dynamic chain of events to occur; an
initial system snapshot may do more good in

identifying the problem and its source than most other actions
that can be taken at this stage. From an
evidentiary standpoint, it is much better to get a snapshot of the
system as-is rather than doing so after
incident handlers, system administrators, and others have
inadvertently altered the state of the machine
during the investigation. Users and system administrators
should be made aware of the steps that they
should take to preserve evidence. See NIST SP 800-86, Guide to
Integrating Forensic Techniques into
Incident Response, for additional information on preserving
evidence.
42
NIST SP 800-86, Guide to Integrating Forensic Techniques
into Incident Response, provides detailed information on
establishing a forensic capability. It focuses on forensic
techniques for PCs, but much of the material is applicable to
other
systems. The document can be found at
43
Evidence gathering and handling is not typically performed for
every incident that occurs—for example, most malware
incidents do not merit evidence acquisition. In many

organizations, digital forensics is not needed for most incidents.
44
Searching and Seizing Computers and Obtaining Electronic
Evidence in Criminal Investigati ons, from the Computer Crime
and Intellectual Property Section (CCIPS) of the Department of
Justice, provides legal guidance on evidence gathering. The
document is available at
http://www.cybercrime.gov/ssmanual/index.html.
http://www.cybercrime.gov/ssmanual/index.html
37
3.3.3 Identifying the Attacking Hosts
During incident handling, system owners and others sometimes
want to or need to identify the attacking
host or hosts. Although this information can be important,
incident handlers should generally stay focused
on containment, eradication, and recovery. Identifying an
attacking host can be a time-consuming and
futile process that can prevent a team from achieving its
primary goal—minimizing the business impact.
The following items describe the most commonly performed
activities for attacking host identification:

handlers often focus on the attacking
host’s IP address. The handler may attempt to validate that the
address was not spoofed by verifying
connectivity to it; however, this simply indicates that a host at
that address does or does not respond
to the requests. A failure to respond does not mean the address
is not real—for example, a host may
be configured to ignore pings and traceroutes. Also, the attacker
may have received a dynamic
address that has already been reassigned to someone else.
king Host through Search Engines.
Performing an Internet search using the
apparent source IP address of an attack may lead to more
information on the attack—for example, a
mailing list message regarding a similar attack.
veral groups collect and
consolidate incident data from various
organizations into incident databases. This information sharing
may take place in many forms, such
as trackers and real-time blacklists. The organization can also
check its own knowledge base or issue
tracking system for related activity.
Incident handlers can monitor

communication channels that may be used by an attacking host.
For example, many bots use IRC as
their primary means of communication. Also, attackers may
congregate on certain IRC channels to
brag about their compromises and share information. However,
incident handlers should treat any
such information that they acquire only as a potential lead, not
as fact.
3.3.4 Eradication and Recovery
After an incident has been contained, eradication may be
necessary to eliminate components of the
incident, such as deleting malware and disabling breached user
accounts, as well as identifying and
mitigating all vulnerabilities that were exploited. During
eradication, it is important to identify all affected
hosts within the organization so that they can be remediated.
For some incidents, eradication is either not
necessary or is performed during recovery.
In recovery, administrators restore systems to normal operation,
confirm that the systems are functioning
normally, and (if applicable) remediate vulnerabilities to
prevent similar incidents. Recovery may involve
such actions as restoring systems from clean backups,
rebuilding systems from scratch, replacing

compromised files with clean versions, installing patches,
changing passwords, and tightening network
perimeter security (e.g., firewall rulesets, boundary router
access control lists). Higher levels of system
logging or network monitoring are often part of the recovery
process. Once a resource is successfully
attacked, it is often attacked again, or other resources within the
organization are attacked in a similar
manner.
Eradication and recovery should be done in a phased approach
so that remediation steps are prioritized.
For large-scale incidents, recovery may take months; the intent
of the early phases should be to increase
the overall security with relatively quick (days to weeks) high
value changes to prevent future incidents.
The later phases should focus on longer-term changes (e.g.,
infrastructure changes) and ongoing work to
keep the enterprise as secure as possible.
38
Because eradication and recovery actions are typically OS or

application-specific, detailed
recommendations and advice regarding them are outside the
scope of this document.
3.4 Post-Incident Activity
Figure 3-4. Incident Response Life Cycle (Post-Incident
Activity)
3.4.1 Lessons Learned
One of the most important parts of incident response is also the
most often omitted: learning and
improving. Each incident response team should evolve to reflect
new threats, improved technology, and
lessons learned. Holding a “lessons learned” meeting with all
involved parties after a major incident, and
optionally periodically after lesser incidents as resources
permit, can be extremely helpful in improving
security measures and the incident handling process itself.
Multiple incidents can be covered in a single
lessons learned meeting. This meeting provides a chance to
achieve closure with respect to an incident by
reviewing what occurred, what was done to intervene, and how
well intervention worked. The meeting
should be held within several days of the end of the incident.
Questions to be answered in the meeting

include:
the incident? Were the documented
procedures followed? Were they adequate?
recovery?
time a similar incident occurs?
been improved?
future?
future to detect similar incidents?
39
analyze, and mitigate future incidents?
Small incidents need limited post-incident analysis, with the

exception of incidents performed through
new attack methods that are of widespread concern and interest.
After serious attacks have occurred, it is
usually worthwhile to hold post-mortem meetings that cross
team and organizational boundaries to
provide a mechanism for information sharing. The primary
consideration in holding such meetings is
ensuring that the right people are involved. Not only is it
important to invite people who have been
involved in the incident that is being analyzed, but also it is
wise to consider who should be invited for the
purpose of facilitating future cooperation.
The success of such meetings also depends on the agenda.
Collecting input about expectations and needs
(including suggested topics to cover) from participants before
the meeting increases the likelihood that the
participants’ needs will be met. In addition, establishing rules
of order before or during the start of a
meeting can minimize confusion and discord. Having one or
more moderators who are skilled in group
facilitation can yield a high payoff. Finally, it is also important
to document the major points of
agreement and action items and to communicate them to parties
who could not attend the meeting.

Lessons learned meetings provide other benefits. Reports from
these meetings are good material for
training new team members by showing them how more
experienced team members respond to incidents.
Updating incident response policies and procedures is another
important part of the lessons learned
process. Post-mortem analysis of the way an incident was
handled will often reveal a missing step or an
inaccuracy in a procedure, providing impetus for change.
Because of the changing nature of information
technology and changes in personnel, the incident response
team should review all related documentation
and procedures for handling incidents at designated intervals.
Another important post-incident activity is creating a follow-up
report for each incident, which can be
quite valuable for future use. The report provides a reference
that can be used to assist in handling similar
incidents. Creating a formal chronology of events (including
timestamped information such as log data
from systems) is important for legal reasons, as is creating a
monetary estimate of the amount of damage
the incident caused. This estimate may become the basis for
subsequent prosecution activity by entities

such as the U.S. Attorney General’s office. Follow -up reports
should be kept for a period of time as
specified in record retention policies.
45
3.4.2 Using Collected Incident Data
Lessons learned activities should produce a set of objective and
subjective data regarding each incident.
Over time, the collected incident data should be useful in
several capacities. The data, particularly the
total hours of involvement and the cost, may be used to justify
additional funding of the incident response
team. A study of incident characteristics may indicate systemic
security weaknesses and threats, as well
as changes in incident trends. This data can be put back into the
risk assessment process, ultimately
leading to the selection and implementation of additional
controls. Another good use of the data is
measuring the success of the incident response team. If incident
data is collected and stored properly, it
should provide several measures of the success (or at least the
activities) of the incident response team.
Incident data can also be collected to determine if a change to
incident response capabilities causes a

corresponding change in the team’s performance (e.g.,
improvements in efficiency, reductions in costs).
Furthermore, organizations that are required to report incident
information will need to collect the
45
General Records Schedule (GRS) 24, Information Technology
Operations and Management Records, specifies that
“computer security incident handling, reporting and follow -up
records” should be destroyed “3 years after all necessary
follow-up actions have been completed.” GRS 24 is available
from the National Archives and Records Administration at
http://www.archives.gov/records-mgmt/grs/grs24.html.
http://www.archives.gov/records-mgmt/grs/grs24.html
40
necessary data to meet their requirements. See Section 4 for
additional information on sharing incident
data with other organizations.
Organizations should focus on collecting data that is actionable,
rather than collecting data simply
because it is available. For example, counting the number of

precursor port scans that occur each week
and producing a chart at the end of the year that shows port
scans increased by eight percent is not very
helpful and may be quite time-consuming. Absolute numbers are
not informative—understanding how
they represent threats to the business processes of the
organization is what matters. Organizations should
decide what incident data to collect based on reporting
requirements and on the expected return on
investment from the data (e.g., identifying a new threat and
mitigating the related vulnerabilities before
they can be exploited.) Possible metrics for incident-related
data include:
46
Handling more incidents is not necessarily better—for example,
the number of incidents handled may decrease because of better
network and host security controls,
not because of negligence by the incident response team. The
number of incidents handled is best
taken as a measure of the relative amount of work that the
incident response team had to perform, not
as a measure of the quality of the team, unless it is considered
in the context of other measures that

collectively give an indication of work quality. It is more
effective to produce separate incident
counts for each incident category. Subcategories also can be
used to provide more information. For
example, a growing number of incidents performed by insiders
could prompt stronger policy
provisions concerning background investigatio ns for personnel
and misuse of computing resources
and stronger security controls on internal networks (e.g.,
deploying intrusion detection software to
more internal networks and hosts).
in several ways:
– Total amount of labor spent working on the incident
– Elapsed time from the beginning of the incident to incident
discovery, to the initial impact
assessment, and to each stage of the incident handling process
(e.g., containment, recovery)
– How long it took the incident response team to respond to the
initial report of the incident
– How long it took to report the incident to management and, if
necessary, appropriate external
entities (e.g., US-CERT).
Each Incident. The response to an

incident that has been resolved can be
analyzed to determine how effective it was. The following are
examples of performing an objective
assessment of an incident:
– Reviewing logs, forms, reports, and other incident
documentation for adherence to established
incident response policies and procedures
– Identifying which precursors and indicators of the incident
were recorded to determine how
effectively the incident was logged and identified
– Determining if the incident caused damage before it was
detected
46
Metrics such as the number of incidents handled are generally
not of value in a comparison of multiple organizations
because each organization is likely to have defined key terms
differently. For example, most organizations define “incident”
in terms of their own policies and practices, and what one
organization considers a single incident may be considered
multiple incidents by others. More specific metrics, such as the
number of port scans, are also of little value in
organizational comparisons. For example, it is highly unlikely
that different security systems, such as network intrusion
detection sensors, would all use the same criteria in labeling

activity as a port scan.
41
– Determining if the actual cause of the incident was identified,
and identifying the vector of attack,
the vulnerabilities exploited, and the characteristics of the
targeted or victimized systems,
networks, and applications
– Determining if the incident is a recurrence of a previous
incident
– Calculating the estimated monetary damage from the incident
(e.g., information and critical
business processes negatively affected by the incident)
– Measuring the difference between the initial impact
assessment and the final impact assessment
(see Section 3.2.6)
– Identifying which measures, if any, could have prevented the
incident.
h Incident. Incident response
team members may be asked to assess
their own performance, as well as that of other team members
and of the entire team. Another
valuable source of input is the owner of a resource that was
attacked, in order to determine if the

owner thinks the incident was handled efficiently and if the
outcome was satisfactory.
Besides using these metrics to measure the team’s success,
organizations may also find it useful to
periodically audit their incident response programs. Audi ts will
identify problems and deficiencies that
can then be corrected. At a minimum, an incident response audit
should evaluate the following items
against applicable regulations, policies, and generally accepted
practices:
es, plans, and procedures
3.4.3 Evidence Retention
Organizations should establish policy for how long evidence
from an incident should be retained. Most
organizations choose to retain all evidence for months or years
after the incident ends. The following

factors should be considered during the policy creation:
prosecuted, evidence may need to be retained
until all legal actions have been completed. In some cases, this
may take several years. Furthermore,
evidence that seems insignificant now may become more
important in the future. For example, if an
attacker is able to use knowledge gathered in one attack to
perform a more severe attack later,
evidence from the first attack may be key to explaining how the
second attack was accomplished.
policies that state how long certain types of
data may be kept. For example, an organization may state that
email messages should be retained for
only 180 days. If a disk image contains thousands of emails, the
organization may not want the image
to be kept for more than 180 days unless it is absolutely
necessary. As discussed in Section 3.4.2,
General Records Schedule (GRS) 24 specifies that incident
handling records should be kept for
three years.

42
systems) that is stored as evidence, as well
as hard drives and removable media that are used to hold disk
images, are generally individually
inexpensive. However, if an organization stores many such
components for years, the cost can be
substantial. The organization also must retain functional
computers that can use the stored hardware
and media.
3.5 Incident Handling Checklist
The checklist in Table 3-5 provides the major steps to be
performed in the handling of an incident. Note
that the actual steps performed may vary based on the type of
incident and the nature of individual
incidents. For example, if the handler knows exactly what has
happened based on analysis of indicators
(Step 1.1), there may be no need to perform Steps 1.2 or 1.3 to
further research the activity. The checklist
provides guidelines to handlers on the major steps that should
be performed; it does not dictate the exact
sequence of steps that should always be followed.
Table 3-5. Incident Handling Checklist
Action Completed

Detection and Analysis
1. Determine whether an incident has occurred
1.1 Analyze the precursors and indicators
1.2 Look for correlating information
1.3 Perform research (e.g., search engines, knowledge base)
1.4 As soon as the handler believes an incident has occurred,
begin documenting
the investigation and gathering evidence
2. Prioritize handling the incident based on the relevant factors
(functional impact, information
impact, recoverability effort, etc.)
3. Report the incident to the appropriate internal personnel and
external organizations
Containment, Eradication, and Recovery
4. Acquire, preserve, secure, and document evidence
5. Contain the incident
6. Eradicate the incident
6.1 Identify and mitigate all vulnerabilities that were exploited
6.2 Remove malware, inappropriate materials, and other
components
6.3 If more affected hosts are discovered (e.g., new malware

infections), repeat
the Detection and Analysis steps (1.1, 1.2) to identify all other
affected hosts, then
contain (5) and eradicate (6) the incident for them
7. Recover from the incident
7.1 Return affected systems to an operationally ready state
7.2 Confirm that the affected systems are functioning normally
7.3 If necessary, implement additional monitoring to look for
future related activity
Post-Incident Activity
8. Create a follow-up report
9. Hold a lessons learned meeting (mandatory for major
incidents, optional otherwise)
3.6 Recommendations
The key recommendations presented in this section for handling
incidents are summarized below.
43
quire tools and resources that may be of value during
incident handling. The team will be
more efficient at handling incidents if various tools and
resources are already available to them.

Examples include contact lists, encryption software, network
diagrams, backup devices, digital
forensic software, and port lists.
systems, and applications are
sufficiently secure. Preventing incidents is beneficial to the
organization and also reduces the
workload of the incident response team. Performing periodic
risk assessments and reducing the
identified risks to an acceptable level are effective in reducing
the number of incidents. Awareness of
security policies and procedures by users, IT staff, and
management is also very important.
several types of security
software. Intrusion detection and prevention systems, antivirus
software, and file integrity checking
software are valuable for detecting signs of incidents. Each type
of software may detect incidents that
the other types of software cannot, so the use of several types of
computer security software is highly
recommended. Third-party monitoring services can also be
helpful.
Outside parties may want to report

incidents to the organization—for example, they may believe
that one of the organization’s users is
attacking them. Organizations should publish a phone number
and email address that outside parties
can use to report such incidents.
systems, and a higher baseline level on all
critical systems. Logs from operating systems, services, and
applications frequently provide value
during incident analysis, particularly if auditing was enabled.
The logs can provide information such
as which accounts were accessed and what actions were
performed.
asures the
characteristics of expected activity levels so
that changes in patterns can be more easily identified. If the
profiling process is automated, deviations
from expected activity levels can be detected and reported to
administrators quickly, leading to faster
detection of incidents and operational issues.
applications. Team members who
understand normal behavior should be able to recognize
abnormal behavior more easily. This
knowledge can best be gained by reviewing log entries and
security alerts; the handlers should

become familiar with the typical data and can investigate the
unusual entries to gain more knowledge.
incident may be recorded in several places.
Creating and implementing a log retention policy that specifies
how long log data should be
maintained may be extremely helpful in analysis because older
log entries may show reconnaissance
activity or previous instances of similar attacks.
captured in several logs. Correlating
events among multiple sources can be invaluable in collecting
all the available information for an
incident and validating whether the incident occurred.
events have inconsistent clock settings,
event correlation will be more complicated. Clock discrepancies
may also cause issues from an
evidentiary standpoint.
need to reference information
quickly during incident analysis; a centralized knowledge base
provides a consistent, maintainable
source of information. The knowledge base should include
general information, such as data on

precursors and indicators of previous incidents.
44
that an incident has occurred.
Every step taken, from the time the incident was detected to its
final resolution, should be
documented and timestamped. Information of this nature can
serve as evidence in a court of law if
legal prosecution is pursued. Recording the steps performed can
also lead to a more efficient,
systematic, and less error-prone handling of the problem.
information regarding such things as
vulnerabilities, security breaches, and users that may have
performed inappropriate actions. The team
should ensure that access to incident data is restricted properly,
both logically and physically.
factors. Because of resource limitations,
incidents should not be handled on a first-come, first-served
basis. Instead, organizations should
establish written guidelines that outline how quickly the team
must respond to the incident and what

actions should be performed, based on relevant factors such as
the functional and information impact
of the incident, and the likely recoverability from the incident.
This saves time for the incident
handlers and provides a justification to management and system
owners for their actions.
Organizations should also establish an escalation process for
those instances when the team does not
respond to an incident within the designated time.
organization’s incident response policy.
Organizations should specify which incidents must be reported,
when they must be reported, and to
whom. The parties most commonly notified are the CIO, head of
information security, local
information security officer, other incident response teams
within the organization, and system
owners.
ablish strategies and procedures for containing incidents.
It is important to contain incidents
quickly and effectively to limit their business impact.
Organizations should define acceptable risks in
containing incidents and develop strategies and procedures
accordingly. Containment strategies

should vary based on the type of incident.
handling. The team should clearly
document how all evidence has been preserved. Evidence should
be accounted for at all times. The
team should meet with legal staff and law enforcement agencies
to discuss evidence handling, then
develop procedures based on those discussions.
lists of network connections,
processes, login sessions, open files, network interface
configurations, and the contents of memory.
Running carefully chosen commands from trusted media can
collect the necessary information
without damaging the system’s evidence.
tain system snapshots through full forensic disk images,
not file system backups. Disk images
should be made to sanitized write-protectable or write-once
media. This process is superior to a file
system backup for investigatory and evidentiary purposes.
Imaging is also valuable in that it is much
safer to analyze an image than it is to perform analysis on the
original system because the analysis
may inadvertently alter the original.

learned meetings are extremely
helpful in improving security measures and the incident
handling process itself.
45
4. Coordination and Information Sharing
The nature of contemporary threats and attacks makes it more
important than ever for organizations to
work together during incident response. Organizations should
ensure that they effectively coordinate
portions of their incident response activities with appropriate
partners. The most important aspect of
incident response coordination is information sharing, where
different organizations share threat, attack,
and vulnerability information with each other so that each
organization’s knowledge benefits the other.
Incident information sharing is frequently mutually beneficial
because the same threats and attacks often
affect multiple organizations simultaneously.
As mentioned in Section 2, coordinating and sharing
information with partner organizations can

strengthen the organization’s ability to effectively respond to IT
incidents. For example, if an organization
identifies some behavior on its network that seems suspicious
and sends information about the event to a
set of trusted partners, someone else in that network may have
already seen similar behavior and be able
to respond with additional details about the suspicious activity,
including signatures, other indicators to
look for, or suggested remediation actions. Collaboration with
the trusted partner can enable an
organization to respond to the incident more quickly and
efficiently than an organization operating in
isolation.
This increase in efficiency for standard incident response
techniques is not the only incentive for cross-
organization coordination and information sharing. Another
incentive for information sharing is the
ability to respond to incidents using techniques that may not be
available to a single organization,
especially if that organization is small to medium size. For
example, a small organization that identifies a
particularly complex instance of malware on its network may
not have the in-house resources to fully

analyze the malware and determine its effect on the system. In
this case, the organization may be able to
leverage a trusted information sharing network to effectively
outsource the analysis of this malware to
third party resources that have the adequate technical
capabilities to perform the malware analysis.
This section of the document highlights coordination and
information sharing. Section 4.1 presents an
overview of incident response coordination and focuses on the
need for cross-organization coordination to
supplement organization incident response processes. Section
4.2 discusses techniques for information
sharing across organizations, and Section 4.3 examines how to
restrict what information is shared or not
shared with other organizations.
4.1 Coordination
As discussed in Section 2.3.4, an organization may need to
interact with several types of external
organizations in the course of conducting incident response
activities. Examples of these organizations
include other incident response teams, law enforcement
agencies, Internet service providers, and

constituents and customers. An organization’s incident response
team should plan its incident
coordination with those parties before incidents occur to ensure
that all parties know their roles and that
effective lines of communication are established. Figure 4-1
provides a sample view into an organization
performing coordination at every phase of the incident response
lifecycle, highlighting that coordination
is valuable throughout the lifecycle.
46
Figure 4-1. Incident Response Coordination
4.1.1 Coordination Relationships
An incident response team within an organization may
participate in different types of coordination
arrangements, depending on the type of organization with which
it is coordinating. For example, the team
members responsible for the technical details of incident
response may coordinate with operational
colleagues at partner organizations to share strategies for

mitigating an attack spanning multiple
organizations. Alternatively, during the same incident, the
incident response team manager may
coordinate with ISACs to satisfy necessary reporting
requirements and seek advice and additional
resources for successfully responding to the incident. Table 4-1
provides some examples of coordination
relationships that may exist when collaborating with outside
organizations.
47
Table 4-1. Coordination Relationships
Category Definition Information Shared
Team-to-
team
Team-to-team relationships exist whenever
technical incident responders in different
organizations collaborate with their peers
during any phase of the incident handling life
cycle. The organizations participating in this
type of relationship are usually peers without
any authority over each other and choose to

share information, pool resources, and reuse
knowledge to solve problems common to both
teams.
The information most frequently shared in team-to-
team relationships is tactical and technical (e.g.,
technical indicators of compromise, suggested
remediation actions) but may also include other
types of information (plans, procedures, lessons
learned) if conducted as part of the Preparation
phase.
Team-to-
coordinating
team
Team-to-coordinating team relationships exist
between an organizational incident response
team and a separate organization that acts as
a central point for coordinated incident
response and management such as US-
CERT or an ISAC. This type of relationship
may include some degree of required
reporting from the member organizations by
the coordinating body, as well as the
expectation that the coordinating team will
disseminate timely and useful information to
participating member organizations.
Teams and coordinating teams frequently share
tactical, technical information as well as information
regarding threats, vulnerabilities, and risks to the
community served by the coordinating team. The
coordinating team may also need specific impact
information about incidents in order to help make
decisions on where to focus its resources and

attention.
Coordinating
team-to-
coordinating
team
Relationships between multiple coordinating
teams such as US-CERT and the ISACs exist
to share information relating to cross-cutting
incidents which may affect multiple
communities. The coordinating teams act on
behalf of their respective community member
organizations to share information on the
nature and scope of cross-cutting incidents
and reusable mitigation strategies to assist in
inter-community response.
The type of information shared by coordinating
teams with their counterparts often consists of
periodical summaries during “steady state”
operations, punctuated by the exchange of tactical,
technical details, response plans, and impact or risk
assessment information during coordinated incident
response activities.
Organizations may find it challenging to build the relationships
needed for coordination. Good places to
start building a community include the industry sector that the
organization belongs to and the geographic
region where the organization operates. An organization’s
incident response team can try to form

relationships with other teams (at the team-to-team level) within
its own industry sector and region, or
join established bodies within the industry sector that already
facilitate information sharing. Another
consideration for building relationships is that some
relationships are mandatory and others voluntary; for
example, team-to-coordinating team relationships are often
mandatory, while team-to-team relationships
are usually voluntary. Organizations pursue voluntary
relationships because they fulfill mutual self-
interests. Mandatory relationships are usually defined by a
regulatory body within the industry or by
another entity.
4.1.2 Sharing Agreements and Reporting Requirements
Organizations trying to share information with external
organizations should consult with their legal
department before initiating any coordination efforts. There
may be contracts or other agreements that
need to be put into place before discussions occur. An example
is a nondisclosure agreement (NDA) to
protect the confidentiality of the organization’s most sensitive
information. Organizations should also
consider any existing requirements for reporting, such as

sharing incident information with an ISAC or
reporting incidents to a higher-level CIRT.
48
4.2 Information Sharing Techniques
Information sharing is a key element of enabling coordination
across organizations. Even the smallest
organizations need to be able to share incident information with
peers and partners in order to deal with
many incidents effectively. Organizations should perform such
information sharing throughout the
incident response life cycle and not wait until an incident has
been fully resolved before sharing details of
it with others. Section 4.3 discusses the types of incident
information that organizations may or may not
want to share with others.
This section focuses on techniques for information sharing.
Section 4.2.1 looks at ad hoc methods, while
Section 4.2.2 examines partially automated methods. Finally,
Section 4.2.3 discusses security

considerations related to information sharing.
4.2.1 Ad Hoc
Most incident information sharing has traditionally occurred
through ad hoc methods, such as email,
instant messaging clients, and phone. Ad hoc information
sharing mechanisms normally rely on an
individual employee’s connections with employees in incident
response teams of partner organizations.
The employee uses these connections to manually share
information with peers and coordinate with them
to construct strategies for responding to an incident. Depending
on the size of the organization, these ad
hoc techniques may be the most cost-effective way of sharing
information with partner organizations.
However, due to the informal nature of ad hoc information
sharing, it is not possible to guarantee that the
information sharing processes will always operate. For example,
if a particularly well-connected
employee resigns from an incident response team, that team may
temporarily lose the majority of
information sharing channels it relies on to effectively
coordinate with outside organizations.

Ad hoc information sharing methods are also largely
unstandardized in terms of what information is
communicated and how that communication occurs. Because of
the lack of standardization, they tend to
require manual intervention and to be more resource-intensive
to process than the alternative, partially
automated methods. Whenever possible an organization should
attempt to formalize its information
sharing strategies through formal agreements with partner
organizations and technical mechanisms that
will help to partially automate the sharing of information.
4.2.2 Partially Automated
Organizations should attempt to automate as much of the
information sharing process as possible to make
cross-organizational coordination efficient and cost effective. In
reality, it will not be possible to fully
automate the sharing of all incident information, nor will it be
desirable due to security and trust
considerations. Organizations should attempt to achieve a
balance of automated information sharing
overlaid with human-centric processes for managing the
information flow.

When engineering automated information sharing solutions,
organizations should first consider what
types of information they will communicate with partners. The
organization may want to construct a
formal data dictionary enumerating all entities and relationships
between entities that they will wish to
share. Once the organization understands the types of
information they will share, it is necessary to
construct formal, machine-processable models to capture this
information. Wherever possible, an
organization should use existing data exchange standards for
representing the information they need to
49
share.
47
The organization should work with its partner organizations
when deciding on the data exchange
models to ensure that the standards selected are compatible with
the partner organization’s incident
response systems. When selecting existing data exchange
models, organizations may prefer to select

multiple models that model different aspects of the incident
response domain and then leverage these
models in a modular fashion, communicating only the
information needed at a specific decision point in
the life cycle. Appendix E provides a non-exhaustive list of
existing standards defining data exchange
models that are applicable to the incident response domain.
In addition to selecting the data exchange models for sharing
incident information, an organization must
also work with its partner organizations to agree on the
technical transport mechanisms for enabling the
information exchange to occur in an automated fashion. These
transport mechanisms include, at a
minimum, the transport protocol for exchanging the
information, the architectural model for
communicating with an information resource, and the applicable
ports and domain names for accessing an
information resource in a particular organization. For example,
a group of partner organizations may
decide to exchange incident information using a
Representational State Transfer (REST) architecture to
exchange IODEF/Real-Time Inter-Network Defense (RID) data
over Hypertext Transfer Protocol Secure

(HTTPS) on port 4590 of a specific domain name within each
organization’s DMZ.
4.2.3 Security Considerations
There are several security considerations that incident response
teams should consider when planning
their information sharing. One is being able to designate who
can see which pieces of incident
information (e.g., protection of sensitive information). It may
also be necessary to perform data
sanitization or scrubbing to remove sensitive pieces of data
from the incident information without
disturbing the information on precursors, indicators, and other
technical information. See Section 4.3 for
more information on granular information sharing. The incident
response team should also ensure that the
necessary measures are taken to protect information shared with
the team by other organizations.
There are also many legal issues to consider regarding data
sharing. See Section 4.1.2 for additional
information.
4.3 Granular Information Sharing

Organizations need to balance the benefits of information
sharing with the drawbacks of sharing sensitive
information, ideally sharing the necessary information and only
the necessary information with the
appropriate parties. Organizations can think of their incident
information as being comprised of two types
of information: business impact and technical. Business impact
information is often shared in the context
of a team-to-coordinating-team relationship as defined in
Section 4.1.1, while technical information is
often shared within all three types of coordination relationships.
This section discusses both types of
information and provides recommendations for performing
granular information sharing.
4.3.1 Business Impact Information
Business impact information involves how the incident is
affecting the organization in terms of mission
impact, financial impact, etc. Such information, at least at a
summary level, is often reported to higher-
level coordinating incident response teams to communicate an
estimate of the damage caused by the
incident. Coordinating response teams may need this impact
information to make decisions regarding the

47
According to the National Technology Transfer and
Advancement Act (NTTAA), “all Federal agencies and
departments
shall use technical standards that are developed or adopted by
voluntary consensus standards bodies”. See
http://standards.gov/nttaa.cfm for more details.
http://standards.gov/nttaa.cfm
50
degree of assistance to provide to the reporting organization. A
coordinating team may also use this
information to make decisions relative to how a specific
incident will affect other organizations in the
community they represent.
Coordinating teams may require member organizations to report
on some degree of business impact
information. For example, a coordinating team may require a
member organization to report impact
information using the categories defined in Section 3.2.6. In
this case, for a hypothetical incident an

organization would report that it has a functional impact of
medium, an information impact of none, and
will require extended recoverability time. This high-level
information would alert the coordinating team
that the member organization requires some level of additional
resources to recover from the incident.
The coordinating team could then pursue additional
communication with the member organization to
determine how many resources are required as well as the type
of resources based on the technical
information provided about the incident.
Business impact information is only useful for reporting to
organizations that have some interest in
ensuring the mission of the organization experiencing the
incident. In many cases, incident response
teams should avoid sharing business impact information with
outside organizations unless there is a clear
value proposition or formal reporting requirements. When
sharing information with peer and partner
organizations, incident response teams should focus on
exchanging technical information as outlined in
Section 4.3.2.

4.3.2 Technical Information
There are many different types of technical indicators
signifying the occurrence of an incident within an
organization. These indicators originate from the variety of
technical information associated with
incidents, such as the hostnames and IP addresses of attacking
hosts, samples of malware, precursors and
indicators of similar incidents, and types of vulnerabilities
exploited in an incident. Section 3.2.2 provides
an overview of how organizations should collect and utilize
these indicators to help identify an incident
that is in progress. In addition, Section 3.2.3 provides a listing
of common sources of incident indicator
data.
While organizations gain value from collecting their own
internal indicators, they may gain additional
value from analyzing indicators received from partner
organizations and sharing internal indicators for
external analysis and use. If the organization receives external
indicator data pertaining to an incident they
have not seen, they can use that indicator data to identify the
incident as it begins to occur. Similarly, an
organization may use external indicator data to detect an

ongoing incident that it was not aware of due to
the lack of internal resources to capture the specific indicator
data. Organizations may also benefit from
sharing their internal indicator data with external organizations.
For example, if they share technical
information pertaining to an incident they are experiencing, a
partner organization may respond with a
suggested remediation strategy for handling that incident.
Organizations should share as much of this information as
possible; however, there may be both security
and liability reasons why an organization would not want to
reveal the details of an exploited
vulnerability. External indicators, such as the general
characteristics of attacks and the identity of
attacking hosts, are usually safe to share with others.
Organizations should consider which types of
technical information should or should not be shared with
various parties, and then endeavor to share as
much of the appropriate information as possible with other
organizations.
Technical indicator data is useful when it allows an
organization to identify an actual incident. However,

not all indicator data received from external sources will pertain
to the organization receiving it. In some
51
cases, this external data will generate false positives within the
receiving organization's network and may
cause resources to be spent on nonexistent problems.
Organizations participating in incident information sharing
should have staff skilled in taking technical
indicator information from sharing communities and
disseminating that information throughout the
enterprise, preferably in an automated way. Organizations
should also attempt to ensure that they only
share an indicator for which they have a relatively high level of
confidence that it signifies an actual
incident.
4.4 Recommendations
The key recommendations presented in this section for handling
incidents are summarized below.
ith external parties before

incidents occur. Examples of external
parties include other incident response teams, law enforcement
agencies, Internet service providers,
and constituents and customers. This planning helps ensure that
all parties know their roles and that
effective lines of communication are established.
coordination efforts. There may be
contracts or other agreements that need to be put into place
before discussions occur.
Perform incident information sharing throughout the incident
response life cycle. Information
sharing is a key element of enabling coordination across
organizations. Organizations should not wait
until an incident has been fully resolved before sharing details
of it with others.
process as possible. This makes cross-
organizational coordination efficient and cost effective.
Organizations should attempt to achieve a
balance of automated information sharing overlaid with human-
centric processes for managing the
information flow.
drawbacks of sharing sensitive
information. Ideally organizations should share the necessary
information and only the necessary

information with the appropriate parties. Business impact
information is often shared in a team-to-
coordinating team relationship, while technical information is
often shared within all types of
coordination relationships. When sharing information with peer
and partner organizations, incident
response teams should focus on exchanging technical
information.
possible with other organizations.
Organizations should consider which types of technical
information should or should not be shared
with various parties. For example, external indicators, such as
the general characteristics of attacks
and the identity of attacking hosts, are usually safe to share
with others, but there may be both
security and liability reasons why an organization would not
want to reveal the details of an exploited
vulnerability.

52
Appendix A—Incident Handling Scenarios
Incident handling scenarios provide an inexpensive and
effective way to build incident response skills and
identify potential issues with incident response processes. The
incident response team or team members
are presented with a scenario and a list of related questions. The
team then discusses each question and
determines the most likely answer. The goal is to determine
what the team would really do and to
compare that with policies, procedures, and generally
recommended practices to identify discrepancies or
deficiencies. For example, the answer to one question may
indicate that the response would be delayed
because the team lacks a piece of software or because another
team does not provide off-hours support.
The questions listed below are applicable to almost any
scenario. Each question is followed by a reference
to the related section(s) of the document. After the questions are
scenarios, each of which is followed by
additional incident-specific questions. Organizations are
strongly encouraged to adapt these questions and
scenarios for use in their own incident response exercises.
48

A.1 Scenario Questions
Preparation:
1. Would the organization consider this activity to be an
incident? If so, which of the organization’s
policies does this activity violate? (Section 2.1)
2. What measures are in place to attempt to prevent this type of
incident from occurring or to limit
its impact? (Section 3.1.2)
Detection and Analysis:
1. What precursors of the incident, if any, might the
organization detect? Would any precursors
cause the organization to take action before the incident
occurred? (Sections 3.2.2, 3.2.3)
2. What indicators of the incident might the organization
detect? Which indicators would cause
someone to think that an incident might have occurred?
(Sections 3.2.2, 3.2.3)
3. What additional tools might be needed to detect this
particular incident? (Section 3.2.3)
4. How would the incident response team analyze and validate
this incident? What personnel would
be involved in the analysis and validation process? (Section
3.2.4)
5. To which people and groups within the organization would
the team report the incident? (Section

3.2.7)
6. How would the team prioritize the handling of this incident?
(Section 3.2.6)
Containment, Eradication, and Recovery:
1. What strategy should the organization take to contain the
incident? Why is this strategy preferable
to others? (Section 3.3.1)
2. What could happen if the incident were not contained?
(Section 3.3.1)
3. What additional tools might be needed to respond to this
particular incident? (Sections 3.3.1,
3.3.4)
4. Which personnel would be involved in the containment,
eradication, and/or recovery processes?
(Sections 3.3.1, 3.3.4)
48
For additional information on exercises, see NIST SP 800-84,
Guide to Test, Training, and Exercise Programs for IT Plans
and Capabilities, which is available at

53
5. What sources of evidence, if any, should the organization
acquire? How would the evidence be
acquired? Where would it be stored? How long should it be
retained? (Sections 3.2.5, 3.3.2, 3.4.3)
Post-Incident Activity:
1. Who would attend the lessons learned meeting regarding this
incident? (Section 3.4.1)
2. What could be done to prevent similar incidents from
occurring in the future? (Section 3.1.2)
3. What could be done to improve detection of similar
incidents? (Section 3.1.2)
General Questions:
1. How many incident response team members would participate
in handling this incident? (Section
2.4.3)
2. Besides the incident response team, what groups within the
organization would be involved in
handling this incident? (Section 2.4.4)
3. To which external parties would the team report the incident?
When would each report occur?
How would each report be made? What information would you
report or not report, and why?
(Section 2.3.2)
4. What other communications with external parties may occur?

(Section 2.3.2)
5. What tools and resources would the team use in handling this
incident? (Section 3.1.1)
6. What aspects of the handling would have been different if the
incident had occurred at a different
day and time (on-hours versus off-hours)? (Section 2.4.2)
7. What aspects of the handling would have been different if the
incident had occurred at a different
physical location (onsite versus offsite)? (Section 2.4.2)
A.2 Scenarios
Scenario 1: Domain Name System (DNS) Server Denial of
Service (DoS)
On a Saturday afternoon, external users start having problems
accessing the organization’s public
websites. Over the next hour, the problem worsens to the point
where nearly every access attempt fails.
Meanwhile, a member of the organization’s networking staff
responds to alerts from an Internet border
router and determines that the organization’s Internet bandwidth
is being consumed by an unusuall y large
volume of User Datagram Protocol (UDP) packets to and from
both the organization’s public DNS
servers. Analysis of the traffic shows that the DNS servers are
receiving high volumes of requests from a

single external IP address. Also, all the DNS requests from that
address come from the same source port.
The following are additional questions for this scenario:
1. Whom should the organization contact regarding the external
IP address in question?
2. Suppose that after the initial containment measures were put
in place, the network administrators
detected that nine internal hosts were also attempting the same
unusual requests to the DNS
server. How would that affect the handling of this incident?
3. Suppose that two of the nine internal hosts disconnected from
the network before their system
owners were identified. How would the system owners be
identified?
Scenario 2: Worm and Distributed Denial of Service (DDoS)
Agent Infestation
On a Tuesday morning, a new worm is released; it spreads itself
through removable media, and it can
copy itself to open Windows shares. When the worm infects a
host, it installs a DDoS agent. The
54
organization has already incurred widespread infections before

antivirus signatures become available
several hours after the worm started to spread.
1. How would the incident response team identify all infected
hosts?
2. How would the organization attempt to prevent the worm
from entering the organization before
antivirus signatures were released?
3. How would the organization attempt to prevent the worm
from being spread by infected hosts
before antivirus signatures were released?
4. Would the organization attempt to patch all vulnerable
machines? If so, how would this be done?
5. How would the handling of this incident change if infected
hosts that had received the DDoS
agent had been configured to attack another organization’s
website the next morning?
6. How would the handling of this incident change if one or
more of the infected hosts contained
sensitive personally identifiable information regarding the
organization’s employees?
7. How would the incident response team keep the
organization’s users informed about the status of
the incident?
8. What additional measures would the team perform for hosts
that are not currently connected to

the network (e.g., staff members on vacation, offsite employees
who connect occasionally)?
Scenario 3: Stolen Documents
On a Monday morning, the organization’s legal department
receives a call from the Federal Bureau of
Investigation (FBI) regarding some suspicious activity
involving the organization’s systems. Later that
day, an FBI agent meets with members of management and the
legal department to discuss the activity.
The FBI has been investigating activity involving public posting
of sensitive government documents, and
some of the documents reportedly belong to the organization.
The agent asks for the organization’s
assistance, and management asks for the incident response
team’s assistance in acquiring the necessary
evidence to determine if these documents are legitimate or not
and how they might have been leaked.
1. From what sources might the incident response team gather
evidence?
2. What would the team do to keep the investigation
confidential?
3. How would the handling of this incident change if the team
identified an internal host responsible

for the leaks?
found a rootkit installed on the
internal host responsible for the leaks?
Scenario 4: Compromised Database Server
On a Tuesday night, a database administrator performs some
off-hours maintenance on several production
database servers. The administrator notices some unfamiliar and
unusual directory names on one of the
servers. After reviewing the directory listings and viewing some
of the files, the administrator concludes
that the server has been attacked and calls the incident response
team for assistance. The team’s
investigation determines that the attacker successfully gained
root access to the server six weeks ago.
1. What sources might the team use to determine when the
compromise had occurred?
55
found that the database server had

been running a packet sniffer and capturing passwords from the
network?
found that the server was running a
process that would copy a database containing sensiti ve
customer information (including
personally identifiable information) each night and transfer it to
an external address?
discovered a rootkit on the server?
Scenario 5: Unknown Exfiltration
On a Sunday night, one of the organization’s network intrusion
detection sensors alerts on anomalous
outbound network activity involving large file transfers. The
intrusion analyst reviews the alerts; it
appears that thousands of .RAR files are being copied from an
internal host to an external host, and the
external host is located in another country. The analyst contacts
the incident response team so that it can
investigate the activity further. The team is unable to see what
the .RAR files hold because their contents
are encrypted. Analysis of the internal host containing the .RAR
files shows signs of a bot installation.

1. How would the team determine what was most likely inside
the .RAR files? Which other teams
might assist the incident response team?
2. If the incident response team determined that the initial
compromise had been performed through
a wireless network card in the internal host, how would the
team further investigate this activity?
3. If the incident response team determined that the internal
host was being used to stage sensitive
files from other hosts within the enterprise, how would the team
further investigate this activity?
Scenario 6: Unauthorized Access to Payroll Records
On a Wednesday evening, the organization’s physical security
team receives a call from a payroll
administrator who saw an unknown person leave her office, run
down the hallway, and exit the building.
The administrator had left her workstation unlocked and
unattended for only a few minutes. The payroll
program is still logged in and on the main menu, as it was when
she left it, but the administrator notices
that the mouse appears to have been moved. The incident
response team has been asked to acquire
evidence related to the incident and to determine what actions
were performed.

1. How would the team determine what actions had been
performed?
2. How would the handling of this incident differ if the payroll
administrator had recognized the
person leaving her office as a former payroll department
employee?
3. How would the handling of this incident differ if the team
had reason to believe that the person
was a current employee?
4. How would the handling of this incident differ if the physical
security team determined that the
person had used social engineering techniques to gain physical
access to the building?
5. How would the handling of this incident differ if logs from
the previous week showed an
unusually large number of failed remote login attempts using
the payroll administrator’s user ID?
6. How would the handling of this incident differ if the incident
response team discovered that a
keystroke logger was installed on the computer two weeks
earlier?
56
Scenario 7: Disappearing Host
On a Thursday afternoon, a network intrusion detection sensor

records vulnerability scanning activity
directed at internal hosts that is being generated by an internal
IP address. Because the intrusion detection
analyst is unaware of any authorized, scheduled vulnerability
scanning activity, she reports the activity to
the incident response team. When the team begins the analysis,
it discovers that the activity has stopped
and that there is no longer a host using the IP address.
1. What data sources might contain information regarding the
identity of the vulnerability scanning
host?
2. How would the team identify who had been performing the
vulnerability scans?
3. How would the handling of this incident differ if the
vulnerability scanning were directed at the
organization’s most critical hosts?
vulnerability scanning were directed at
external hosts?
5. How would the handling of this incident differ if the internal
IP address was associated with the
organization’s wireless guest network?
6. How would the handling of this incident differ if the physical
security staff discovered that

someone had broken into the facility half an hour before the
vulnerability scanning occurred?
Scenario 8: Telecommuting Compromise
On a Saturday night, network intrusion detection software
records an inbound connection originating
from a watchlist IP address. The intrusion detection analyst
determines that the connection is being made
to the organization’s VPN server and contacts the incident
response team. The team reviews the intrusion
detection, firewall, and VPN server logs and identifies the user
ID that was authenticated for the session
and the name of the user associated with the user ID.
1. What should the team’s next step be (e.g., calling the user at
home, disabling the user ID,
disconnecting the VPN session)? Why should this step be
performed first? What step should be
performed second?
2. How would the handling of this incident differ if the external
IP address belonged to an open
proxy?
3. How would the handling of this incident differ if the ID had
been used to initiate VPN
connections from several external IP addresses without the
knowledge of the user?

4. Suppose that the identified user’s computer had become
compromised by a game containing a
Trojan horse that was downloaded by a family member. How
would this affect the team’s
analysis of the incident? How would this affect evidence
gathering and handling? What should
the team do in terms of eradicating the incident from the user’s
computer?
5. Suppose that the user installed antivirus software and
determined that the Trojan horse had
included a keystroke logger. How would this affect the handling
of the incident? How would this
affect the handling of the incident if the user were a system
administrator? How would this affect
the handling of the incident if the user were a high-ranking
executive in the organization?
57
Scenario 9: Anonymous Threat
On a Thursday afternoon, the organization’s physical security
team receives a call from an IT manager,
reporting that two of her employees just received anonymous
threats against the organization’s systems.

Based on an investigation, the physical security team believes
that the threats should be taken seriously
and notifies the appropriate internal teams, including the
incident response team, of the threats.
1. What should the incident response team do differently, if
anything, in response to the notification
of the threats?
2. What impact could heightened physical security controls have
on the team’s responses to
incidents?
Scenario 10: Peer-to-Peer File Sharing
The organization prohibits the use of peer-to-peer file sharing
services. The organization’s network
intrusion detection sensors have signatures enabled that can
detect the usage of several popular peer-to-
peer file sharing services. On a Monday evening, an intrusion
detection analyst notices that several file
sharing alerts have occurred during the past three hours, all
involving the same internal IP address.
1. What factors should be used to prioritize the handling of this
incident (e.g., the apparent content
of the files that are being shared)?
2. What privacy considerations may impact the handling of this

incident?
computer performing peer-to-peer file
sharing also contains sensitive personally identifiable
information?
Scenario 11: Unknown Wireless Access Point
On a Monday morning, the organization’s help desk receives
calls from three users on the same floor of a
building who state that they are having problems with their
wireless access. A network administrator who
is asked to assist in resolving the problem brings a laptop with
wireless access to the users’ floor. As he
views his wireless networking configuration, he notices that
there is a new access point listed as being
available. He checks with his teammates and determines that
this access point was not deployed by his
team, so that it is most likely a rogue access point that was
established without permission.
1. What should be the first major step in handling this incident
(e.g., physically finding the rogue
access point, logically attaching to the access point)?
2. What is the fastest way to locate the access point? What is
the most covert way to locate the
access point?
3. How would the handling of this incident differ if the access

point had been deployed by an
external party (e.g., contractor) temporarily working at the
organization’s office?
4. How would the handling of this incident differ if an intrusion
detection analyst reported signs of
suspicious activity involving some of the workstations on the
same floor of the building?
5. How would the handling of this incident differ if the access
point had been removed while the
team was still attempting to physically locate it?
58
Appendix B—Incident-Related Data Elements
Organizations should identify a standard set of incident-related
data elements to be collected for each
incident. This effort will not only facilitate more effective and
consistent incident handling, but also assist
the organization in meeting applicable incident reporting
requirements. The organization should designate
a set of basic elements (e.g., incident reporter’s name, phone
number, and location) to be collected when

the incident is reported and an additional set of elements to be
collected by the incident handlers during
their response. The two sets of elements would be the basis for
the incident reporting database, previously
discussed in Section 3.2.5. The lists below provide suggestions
of what information to collect for
incidents and are not intended to be comprehensive. Each
organization should create its own list of
elements based on several factors, including its incident
response team model and structure and its
definition of the term “incident.”
B.1 Basic Data Elements
– Name
– Role
– Organizational unit (e.g., agency, department, division, team)
and affiliation
– Email address
– Phone number
– Location (e.g., mailing address, office room number)

– Status change date/timestamps (including time zone): when
the incident started, when the
incident was discovered/detected, when the incident was
reported, when the incident was
resolved/ended, etc.
– Physical location of the incident (e.g., city, state)
– Current status of the incident (e.g., ongoing attack)
– Source/cause of the incident (if known), including hostnames
and IP addresses
– Description of the incident (e.g., how it was detected, what
occurred)
– Description of affected resources (e.g., networks, hosts,
applications, data), including systems’
hostnames, IP addresses, and function
– If known, incident category, vectors of attack associated with
the incident, and indicators related
to the incident (traffic patterns, registry keys, etc.)
– Prioritization factors (functional impact, information impact,
recoverability, etc.)
– Mitigating factors (e.g., stolen laptop containing sensitive
data was using full disk encryption)
– Response actions performed (e.g., shut off host, disconnected
host from network)
– Other organizations contacted (e.g., software vendor)

59
B.2 Incident Handler Data Elements
– Log of actions taken by all handlers
– Contact information for all involved parties
– List of evidence gathered
unpatched host)
49

49
The business impact of the incident could either be a
description of the incident’s effect (e.g., accounting department
unable
to perform tasks for two days) or an impact category based on
the cost (e.g., a “major” incident has a cost of over $100,000).
60
Appendix C—Glossary
Selected terms used in the publication are defined below.
Baselining: Monitoring resources to determine typical
utilization patterns so that significant deviations
can be detected.
Computer Security Incident: See “incident.”
Computer Security Incident Response Team (CSIRT): A
capability set up for the purpose of assisting
in responding to computer security-related incidents; also called
a Computer Incident Response Team
(CIRT) or a CIRC (Computer Incident Response Center,

Computer Incident Response Capability).
Event: Any observable occurrence in a network or system.
False Positive: An alert that incorrectly indicates that malicious
activity is occurring.
Incident: A violation or imminent threat of violation of
computer security policies, acceptable use
policies, or standard security practices.
Incident Handling: The mitigation of violations of security
policies and recommended practices.
Incident Response: See “incident handling.”
Indicator: A sign that an incident may have occurred or may be
currently occurring.
Intrusion Detection and Prevention System (IDPS): Software
that automates the process of monitoring
the events occurring in a computer system or network and
analyzing them for signs of possible incidents
and attempting to stop detected possible incidents.
Malware: A virus, worm, Trojan horse, or other code-based
malicious entity that successfully infects a
host.
Precursor: A sign that an attacker may be preparing to cause an
incident.

Profiling: Measuring the characteristics of expected activity so
that changes to it can be more easily
identified.
Signature: A recognizable, distinguishing pattern associated
with an attack, such as a binary string in a
virus or a particular set of keystrokes used to gain unauthorized
access to a system.
Social Engineering: An attempt to trick someone into revealing
information (e.g., a password) that can
be used to attack systems or networks.
Threat: The potential source of an adverse event.
Vulnerability: A weakness in a system, application, or network
that is subject to exploitation or misuse.
61
Appendix D—Acronyms
Selected acronyms used in the publication are defined below.
CCIPS Computer Crime and Intellectual Property Section
CERIAS Center for Education and Research in Information

Assurance and Security
CERT
®
/CC CERT
®
Coordination Center
CIO Chief Information Officer
CIRC Computer Incident Response Capability
CIRC Computer Incident Response Center
CIRT Computer Incident Response Team
CISO Chief Information Security Officer
CSIRC Computer Security Incident Response Capability
CSIRT Computer Security Incident Response Team
DDoS Distributed Denial of Service
DHS Department of Homeland Security
DNS Domain Name System
DoS Denial of Service
FAQ Frequently Asked Questions
FBI Federal Bureau of Investigation
FIPS Federal Information Processing Standards

FIRST Forum of Incident Response and Security Teams
FISMA Federal Information Security Management Act
GAO General Accountability Office
GFIRST Government Forum of Incident Response and Security
Teams
GRS General Records Schedule
HTTP HyperText Transfer Protocol
IANA Internet Assigned Numbers Authority
IDPS Intrusion Detection and Prevention System
IETF Internet Engineering Task Force
IP Internet Protocol
IR Interagency Report
IRC Internet Relay Chat
ISAC Information Sharing and Analysis Center
ISP Internet Service Provider
IT Information Technology
ITL Information Technology Laboratory
MAC Media Access Control

MOU Memorandum of Understanding
MSSP Managed Security Services Provider
NAT Network Address Translation
NDA Non-Disclosure Agreement
NIST National Institute of Standards and Technology
NSRL National Software Reference Library
NTP Network Time Protocol
NVD National Vulnerability Database
OIG Office of Inspector General
OMB Office of Management and Budget
OS Operating System
PII Personally Identifiable Information
PIN Personal Identification Number
62
POC Point of Contact
REN-ISAC Research and Education Networking Information
Sharing and Analysis Center

RFC Request for Comment
RID Real-Time Inter-Network Defense
SIEM Security Information and Event Management
SLA Service Level Agreement
SOP Standard Operating Procedure
SP Special Publication
TCP Transmission Control Protocol
TCP/IP Transmission Control Protocol/Internet Protocol
TERENA Trans-European Research and Education Networking
Association
UDP User Datagram Protocol
URL Uniform Resource Locator
US-CERT United States Computer Emergency Readiness Team
VPN Virtual Private Network
63

Appendix E—Resources
The lists below provide examples of resources that may be
helpful in establishing and maintai ning an
incident response capability.
Incident Response Organizations
Organization URL
Anti-Phishing Working Group (APWG)
Computer Crime and Intellectual Property Section (CCIPS),
U.S.
Department of Justice
http://www.cybercrime.gov/
CERT
®
Coordination Center, Carnegie Mellon University (CERT
®
/CC) http://www.cert.org/
European Network and Information Security Agency (ENISA)
http://www.enisa.europa.eu/activities/cert
Forum of Incident Response and Security Teams (FIRST)
Government Forum of Incident Response and Security Teams
(GFIRST)

High Technology Crime Investigation Association (HTCIA)
http://www.htcia.org/
InfraGard http://www.infragard.net/
Internet Storm Center (ISC) http://isc.sans.edu/
National Council of ISACs http://www.isaccouncil.org/
United States Computer Emergency Response Team (US-CERT)
NIST Publications
Resource Name URL
NIST SP 800-53 Revision 3, Recommended Security
Controls for Federal Information Systems and
Organizations
NIST SP 800-83, Guide to Malware Incident Prevention
and Handling
NIST SP 800-84, Guide to Test, Training, and Exercise
Programs for IT Plans and Capabilities
NIST SP 800-86, Guide to Integrating Forensic

Techniques into Incident Response
NIST SP 800-92, Guide to Computer Security Log
Management
NIST SP 800-94, Guide to Intrusion Detection and
Prevention Systems (IDPS)
NIST SP 800-115, Technical Guide to Information
Security Testing and Assessment
NIST SP 800-128, Guide for Security-Focused
Configuration Management of Information Systems
http://www.cybercrime.gov/
http://www.cert.org/
http://www.enisa.europa.eu/activities/cert
http://www.htcia.org/
http://www.infragard.net/
http://isc.sans.edu/

http://www.isaccouncil.org/
64
Data Exchange Specifications Applicable to Incident Handling
Title Description Additional Information
AI Asset Identification http://csrc.nist.gov/publications/
PubsNISTIRs.html#NIST-
IR-7693
ARF Asset Results Format http://csrc.nist.gov/publications/
PubsNISTIRs.html#NIST-
IR-7694
CAPEC Common Attack Pattern Enumeration
and Classification
http://capec.mitre.org/
CCE Common Configuration Enumeration http://cce.mitre.org/
CEE Common Event Expression http://cee.mitre.org/

CPE Common Platform Enumeration http://cpe.mitre.org/
CVE Common Vulnerabilities and Exposures
http://cve.mitre.org/
CVSS Common Vulnerability Scoring System
http://www.first.org/cvss/cvss-guide
CWE Common Weakness Enumeration http://cwe.mitre.org/
CybOX Cyber Observable eXpression http://cybox.mitre.org/
MAEC Malware Attribute Enumeration and
Characterization
http://maec.mitre.org/
OCIL Open Checklist Interactive Language
http://csrc.nist.gov/publications/ PubsNISTIRs.html#NIST-
IR-7692
OVAL Open Vulnerability Assessment
Language
http://oval.mitre.org/
RFC 4765 Intrusion Detection Message Exchange
Format (IDMEF)
RFC 5070 Incident Object Description Exchange
Format (IODEF)

RFC 5901 Extensions to the IODEF for Reporting
Phishing
RFC 5941 Sharing Transaction Fraud Data
RFC 6545 Real-time Inter-network Defense (RID)
RFC 6546 Transport of Real-time Inter-network
Defense (RID) Messages over
HTTP/TLS
SCAP Security Content Automation Protocol
http://csrc.nist.gov/publications/PubsSPs.html #SP-800-
126-Rev.%202
XCCDF Extensible Configuration Checklist
Description Format
http://csrc.nist.gov/publications/ PubsNISTIRs.html#NIST-
IR-7275-r4
http://csrc.nist.gov/publications/PubsNISTIRs.html%23NIST-
IR-7693
IR-7693
IR-7694

IR-7694
http://capec.mitre.org/
http://cce.mitre.org/
http://cee.mitre.org/
http://cpe.mitre.org/
http://cve.mitre.org/
http://www.first.org/cvss/cvss-guide
http://cwe.mitre.org/
http://cybox.mitre.org/
http://maec.mitre.org/
IR-7692
IR-7692
http://oval.mitre.org/
http://csrc.nist.gov/publications/PubsSPs.html%23SP-800-126-
Rev.%202
http://csrc.nist.gov/publications/PubsSPs.html%23SP-800-126-
Rev.%202
IR-7275-r4
IR-7275-r4
65

Appendix F—Frequently Asked Questions
Users, system administrators, information security staff
members, and others within organizations may
have questions about incident response. The following are
frequently asked questions (FAQ).
Organizations are encouraged to customize this FAQ and make
it available to their user community.
1. What is an incident?
In general, an incident is a violation of computer security
policies, acceptable use policies, or
standard computer security practices. Examples of incidents are:
a botnet to send high volumes of
connection requests to one of an
organization’s web servers, causing it to crash.
email that is actually malware;
running the tool has infected their computers and established
connections with an external
host.
and threatens to release the details
to the press if the organization does not pay a designated sum of
money.
gal copies of software to others through
peer-to-peer file sharing services.

2. What is incident handling?
Incident handling is the process of detecting and analyzing
incidents and limiting the incident’s
effect. For example, if an attacker breaks into a system through
the Internet, the incident handling
process should detect the security breach. Incident handlers will
then analyze the data and
determine how serious the attack is. The incident will be
prioritized, and the incident handlers
will take action to ensure that the progress of the incident is
halted and that the affected systems
return to normal operation as soon as possible.
3. What is incident response?
The terms “incident handling” and “incident response” are
synonymous in this document.
50
4. What is an incident response team?
An incident response team (also known as a Computer Security
Incident Response Team
[CSIRT]) is responsible for providing incident response services
to part or all of an organization.
The team receives information on possible incidents,

investigates them, and takes action to ensure
that the damage caused by the incidents is minimized.
5. What services does the incident response team provide?
The particular services that incident response teams offer vary
widely among organizations.
Besides performing incident handling, most teams also assume
responsibility for intrusion
detection system monitoring and management. A team may also
distribute advisories regarding
new threats, and educate users and IT staff on their roles in
incident prevention and handling.
6. To whom should incidents be reported?
Organizations should establish clear points of contact (POC) for
reporting incidents internally.
Some organizations will structure their incident response
capability so that all incidents are
reported directly to the incident response team, whereas others
will use existing support
50
Definitions of “incident handling” and “incident response”
vary widely. For example, CERT
®
/CC uses “incident handling”

to refer to the overall process of incident detection, reporting,
analysis, and response, whereas “incident response” refers
specifically to incident containment, recovery, and notification
of others. See http://www.cert.org/csirts/csirt_faq.html for
more information.
http://www.cert.org/csirts/csirt_faq.html
66
structures, such as the IT help desk, for an initial POC. The
organization should recognize that
external parties, such as other incident response teams, would
report some incidents. Federal
agencies are required under the law to report all incidents to the
United States Computer
Emergency Readiness Team (US-CERT). All organizations are
encouraged to report incidents to
their appropriate Computer Security Incident Response Teams
(CSIRTs). If an organization does
not have its own CSIRT to contact, it can report incidents to
other organizations, including
Information Sharing and Analysis Centers (ISACs).

7. How are incidents reported?
Most organizations have multiple methods for reporting an
incident. Different reporting methods
may be preferable as a result of variations in the skills of the
person reporting the activity, the
urgency of the incident, and the sensitivity of the incident. A
phone number should be established
to report emergencies. An email address may be provided for
informal incident reporting,
whereas a web-based form may be useful in formal incident
reporting. Sensitive information can
be provided to the team by using a public key published by the
team to encrypt the material.
8. What information should be provided when reporting an
incident?
The more precise the information is, the better. For example, if
a workstation appears to have
been infected by malware, the incident report should include as
much of the following data as
practical:
phone number, email address)
hostname, and IP address

-by-step explanation of what happened, including what
was done to the workstation
after the infection was discovered. This explanation should be
detailed, including the exact
wording of messages, such as those displayed by the malware or
by antivirus software alerts.
9. How quickly does the incident response team respond to an
incident report?
The response time depends on several factors, such as the type
of incident, the criticality of the
resources and data that are affected, the severity of the incident,
existing Service Level
Agreements (SLA) for affected resources, the time and day of
the week, and other incidents that
the team is handling. Generally, the highest priority is handling
incidents that are likely to cause
the most damage to the organization or to other organizations.
10. When should a person involved with an incident contact law
enforcement?
Communications with law enforcement agencies should be
initiated by the incident response team
members, the chief information officer (CIO), or other
designated official—users, system

administrators, system owners, and other involved parties
should not initiate contact.
11. What should someone do who discovers that a system has
been attacked?
The person should immediately stop using the system and
contact the incident response team. The
person may need to assist in the initial handling of the
incident—for instance, physically
monitoring the system until incident handlers arrive to protect
evidence on the system.
12. What should someone do who is contacted by the media
regarding an incident?
A person may answer the media’s questions in accordance with
the organization’s policy
regarding incidents and outside parties. If the person is not
qualified to represent the organization
in terms of discussing the incident, the person should make no
comment regarding the incident,
67
other than to refer the caller to the organization’s public affairs
office. This will allow the public

affairs office to provide accurate and consistent information to
the media and the public.
68
Appendix G—Crisis Handling Steps
This is a list of the major steps that should be performed when a
technical professional believes that a
serious incident has occurred and the organization does not have
an incident response capability available.
This serves as a basic reference of what to do for someone who
is faced with a crisis and does not have
time to read through this entire document.
1. Document everything. This effort includes every action that
is performed, every piece of evidence,
and every conversation with users, system owners, and others
regarding the incident.
2. Find a coworker who can provide assistance. Handling the
incident will be much easier if two or
more people work together. For example, one person can
perform actions while the other documents
them.
3. Analyze the evidence to confirm that an incident has

occurred. Perform additional research as
necessary (e.g., Internet search engines, software
documentation) to better understand the evidence.
Reach out to other technical professionals within the
organization for additional help.
4. Notify the appropriate people within the organization. This
should include the chief information
officer (CIO), the head of information security, and the local
security manager. Use discretion when
discussing details of an incident with others; tell only the
people who need to know and use
communication mechanisms that are reasonably secure. (If the
attacker has compromised email
services, do not send emails about the incident.)
5. Notify US-CERT and/or other external organizations for
assistance in dealing with the incident.
6. Stop the incident if it is still in progress. The most common
way to do this is to disconnect affected
systems from the network. In some cases, firewall and router
configurations may need to be modified
to stop network traffic that is part of an incident, such as a
denial of service (DoS) attack.
7. Preserve evidence from the incident. Make backups
(preferably disk image backups, not file system
backups) of affected systems. Make copies of log files that
contain evidence related to the incident.

8. Wipe out all effects of the incident. This effort includes
malware infections, inappropriate materials
(e.g., pirated software), Trojan horse files, and any other
changes made to systems by incidents. If a
system has been fully compromised, rebuild it from scratch or
restore it from a known good backup.
9. Identify and mitigate all vulnerabilities that were expl oited.
The incident may have occurred by
taking advantage of vulnerabilities in operating systems or
applications. It is critical to identify such
vulnerabilities and eliminate or otherwise mitigate them so that
the incident does not recur.
10. Confirm that operations have been restored to normal. Make
sure that data, applications, and
other services affected by the incident have been returned to
normal operations.
11. Create a final report. This report should detail the incident
handling process. It also should provide
an executive summary of what happened and how a formal
incident response capability would have
helped to handle the situation, mitigate the risk, and limit the
damage more quickly.
69

Appendix H—Change Log
Revision 2 Draft 1—January 2012
Editorial:
Technical Changes:
Section 2)
2.3.4.3)
(Section 2.5)
Section 3)
attack vectors (Section 3.2.1)
(Section 3.2.6)
the attacking host (Section 3.3.3)
s (Section 3.4.2)

threats (old Appendix B, new Appendix A)
-related data field suggestions
(old Appendix C, new Appendix B)
sources listings (old Appendix
G, new Appendix E)
Handling Steps to reflect changes made
elsewhere in the publication (old Appendices H and I, new
Appendices F and G)
Deletions:
cate material on forensics, pointed readers to
SP 800-86 for the same information
(Section 3.3.2)
(Sections 4 through 8)
A)
leted print resources list (old Appendix F)
Appendix J)
Revision 2 Final—August 2012
Editorial:

Technical Changes:
aring as a team service (Section 2.5)
-1 into bulleted lists (Section 3.1.1)
(Section 3.2.1)
70
precursors and indicators (Section 3.2.3)
3.3.4)
(Section 4)
incident handling (Appendix E)
sAssignment: Create an Incident Response PolicyLearning
Objectives and Outcomes
Create an incident response policy for a health care

organization.
Explore policy creation for incident response for a health care
organization.Assignment Requirements
You are a security professional for a large, private health care
organization. Users have access to file and application servers,
as well as data storage facilities that contain customer health
information and personally identifiable information (PII).
Sean, your manager, has been asked to provide the latest
version of the organization’s incident response policy. To his
knowledge, no policy exists. He has asked you to research and
create an incident response policy.
For this assignment:
1. Look for at least two incident response policies for
organizations of a similar type to your organization.
2. Download NIST “Computer Security Incident Handling
Guide” SP 800-61 Rev 2 located at
https://www.nist.gov/publications/computer-security-incident-
handling-guide.
3. Based on your research, create an initial draft of a high-level
incident response policy for your organization. Consider Health
Insurance Portability and Accountability Act (HIPAA) and other
health care–related compliance requirements.
4. Create a summary report that includes the draft policy and
justifies the content you included in the draft policy.
5. Provide citations for your sources.Required Resources
Course textbook
Internet accessSubmission Requirements
Format: Microsoft Word (or compatible)
Font: Times New Roman, size 12, double-space
Citation Style: APA
Length: 4–6 pages
Deadline 06/08/2021 –11:59 PM

Computer Security Incident Handling Guide Recommendati

Computer Security Incident Handling Guide Recommendati

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