2016 state of the internet threat advisory dnssec ddos amplification attacks

1

Security
Bulletin:
DNSSEC
Amplification
DDoS

1.0
/
OVERVIEW
/
During
the
past
few
quarters,
Akamai
has
observed
and
successfully
mitigated
a
large

number
of
DNS
reflection
and
amplification
DDoS
attacks
abusing
a
Domain
Name
System
Security

Extension
(DNSSEC)
configured
domain.

As
with
other
DNS
reflection
attacks,
malicious
actors
continue

to
use
open
DNS
resolvers
for
their
own
purpose
-‐-‐
effectively
using
these
resolvers
as
a
shared
botnet.

The
DDoS-‐for-‐hire
underground
market
primarily
utilizes
these
techniques.

Since
the
beginning
of
November
2015,
Akamai
has
detected
and
mitigated
more
than
400
DNS

reflection/amplification
DDoS
attacks
abusing
this
domain.

The
domain
has
been
observed
being
leveraged
to
launch
DDoS
attacks
against
customers
in
multiple

verticals
over
the
same
time
period,
and
it
is
most
likely
the
work
of
attackers
making
use
of
a
DDoS-‐for-‐
Hire
service
that
uses
purchased
VPS
services,
public
proxies,
a
classic
botnet
and
basic
attack
types
such

as
DNS
reflection
attacks,
SYN
floods,
UDP
floods,
SSDP
floods,
NTP
floods,
ICMP
floods
and
even
HTTP

GET
floods.

Traffic
analysis
for
the
attack
campaigns
revealed
that
the
DNS
reflection
and
amplification
attacks
are

abusing
DNSSEC
configured
domains
to
amplify
attack
response.

The
domain
has
been
favored
recently

in
DDoS
attacks
due
to
the
large
response
size
(mostly
because
of
DNSSEC
requirements).

DNSSEC

prevents
the
manipulation
of
DNS
record
responses
where
a
malicious
actor
could
potentially
send
users

to
its
own
site.

This
extra
security
offered
by
DNSSEC
comes
at
a
price
as
attackers
can
leverage
the

larger
domain
sizes
for
DNS
amplification
attacks.

Figure
1
shows
a
DNS
query
request
and
response
for
the
domain.

//
malicious
DNS
query

16:48:58.691108
IP
(tos
0x0,
ttl
247,
id
22126,
offset
0,
flags
[none],
proto
UDP
(17),
length
65)

x.x.x.x.52964
>
x.x.x.x.53:
18344+
[1au]
ANY?
xxx.gov.
(37)

//
response
split
into
one
full
packet
and
2
fragments

23:08:46.213890
IP
(tos
0x0,
ttl
52,
id
36095,
offset
0,
flags
[+],
proto
UDP
(17),
length
1500)

x.x.x.x.53
>
x.x.x.x.4444:
36412|
20/0/1
xxx.gov.
RRSIG,
xxx.gov.
RRSIG,
xxx.gov.
MX
xxx.xxx.gov.
5,
xxx.xxx.gov.
MX

xxx.xxx.gov.
5,
xxx.gov.
RRSIG,
xxx.gov.
TXT
"v=spf1
ip4:63.74.109.6
ip4:63.74.109.10
ip4:63.74.109.20
mx
a:list.
xxx.gov
-‐all",

xxx.gov.
RRSIG,
xxx.gov.
A
63.74.109.2,
xxx.gov.
RRSIG[|domain]

23:08:46.213915
IP
(tos
0x0,
ttl
52,
id
36095,
offset
1480,
flags
[+],
proto
UDP
(17),
length
1500)

x.x.x.x
>
x.x.x.x:
ip-‐proto-‐17

23:08:46.213941
IP
(tos
0x0,
ttl
52,
id
36095,
offset
2960,
flags
[none],
proto
UDP
(17),
length
1139)

x.x.x.x
>
x.x.x.x:
ip-‐proto-‐17

Figure
1:

Malicious
DNS
query
request
and
response
for
the
utilized
domain

TLP:
GREEN

Issue
Date:
2.16.2016
RISK
FACTOR:
HIGH

2

Figure
2
is
a
Wireshark
screenshot
showing
the
DNS
response
for
the
domain
taken
during
a
live
DDoS

campaign.

Figure
2:
DNS
response
for
the
domain
as
seen
in
Wireshark

2.0
/
DNSSEC
/
DNSSEC
is
a
suite
of
Internet
Engineering
Task
Force
(IETF)
specifications
for
security

certain
information
provided
by
DNS.
It
is
essentially
a
set
of
extensions
to
DNS
that
provide
origin

authentication
of
DNS
data,
data
integrity,
and
authentication
denial
of
existence.
These
additional

security
controls
are
designed
to
protect
the
Internet
against
certain
types
of
attacks.
A
list
of
all
RFCs

associated
with
DNSSEC
can
be
found
here:
http://www.dnssec.net/rfc

3
[dot]GOV
domains
in
particular
are
required
to
use
DNSSEC,
making
them
commonly
used
by
attackers

exploiting
this
tactic.

Attackers
will
sometimes
also
create
domains
for
amplification
purposes.

Currently
the
domain

hajjamservices.xyz
is
actively
being
leveraged
in
attacks.
However,
these
domains
are
not
ideal
since

DNS
servers
can
usually
filter
them
out.
[dot]GOV
domains
cannot
be
easily
filtered
without
impacting

regular
user
traffic
to
legitimate
public
web
sites.

3.0
/
Open
Source
Intelligence
(OSINT)
/
Figure
3
shows
a
tweet
informing
that
a
particular
domain
was

being
used
for
DNS
amplification
attack
purposes.
Akamai
has
confirmed
that
during
that
day
multiple

DNS
amplification
attacks
were
launched
against
our
customer
base.

Figure
3:
Tweet
stating
the
domain
being
used
for
DNS
amplification

The
following
comment
was
found
on
hackforums.net

“First
you
gotta
filter
the
list
for
higher
response
sizes,
then
add
the
domain
manually.
It's
can't
be
any

domain,
most
booters
use
"xxx.gov"
for
their
DNS
reflection
attacks.”

Figure
4:
Screenshot
from
Hackforum
regarding
the
use
of
a
specific
domain
when
launching
attacks

4
Postings
like
the
one
above
and
the
previous
screenshot
of
a
twitter
message
indicate
that
the
domain
is

being
leveraged
in
many
more
attacks
beyond
those
targeting
Akamai
customers.

For
customers
under
Akamai
protection,
this
domain
has
been
used
in
several
attacks
over
the
past
6

months
across
multiple
campaigns
affecting
multiple
customers
and
industries.
These
attacks
also
have

been
noted
by
other
security
organizations,
DDoS
companies
and
researchers.

4.0
/
Attack
Tool
Analysis
and
Behavior
/
DNS
reflection
attacks
are
typically
combined
with
other

vectors.

Several
of
the
vectors
leveraged
during
attack
campaigns
all
use
very
common
scripts
in
the

DDoS-‐for-‐hire
market.
These
include
DNS
amp
1.x,
NTP
amp
and
the
Dominate
TCP
attack
script.
The

first
two
are
common
DDoS
reflection
and
amplification
vectors.
The
last
script
is
a
modified
version
of

the
Enhanced
SYN
(ESSYN)
attack
script.
All
three
can
be
obtain
on
the
Internet
and
have
been
analyzed

by
Akamai
SIRT.
These
are
widely
used
on
booter/stresser
sites
witch
provide
a
low
cost/low
skill
entry

point
for
anyone
seeking
to
launch
DDoS
attacks.

The
attack
scripts
result
in
the
following
attack
signatures.

Figure
5
shows
samples
of
attacks
simulated

in
a
lab
environment
using
the
scripts.

/Dominate
TCP
attack
script
lab
simulation

23:05:58.522874
IP
230.213.47.233.21304
>
10.0.20.8.80:
Flags
[SEW],
seq
943587328,
win
0,
length
0

/DNS
Amp
attack
script
v1.1
lab
simulation

11:17:11.564998
IP
(tos
0x0,
ttl
64,
id
45361,
offset
0,
flags
[+],
proto
UDP
(17),
length
1500)

192.168.20.16.53
>
192.168.20.51.51942:
61769|
251/0/1
test.com.
TXT
"Jvvcxjoijcxoivjoixcjiojdiw9jd9wj9jf9w9wj9",

test.com.
A
192.168.50.75,
test.com.
A
192.168.50.76,
test.com.
A
<snip>,
test.com.
A
192.168.50.161[|domain]

/NTP
Amp
attack
script
lab
simulation

13:37:49.430166
IP
192.168.200.128.123
>
192.168.200.129.444:
NTPv2,
Reserved,
length
440

Figure
5:
One
packet
sample
of
each
attack
type
simulated
within
our
lab
environment

The
dominant
attack
is
the
only
one
that
is
spoofing
source
IPs.
This
attack
includes
three
set
flags.

The
flags
are
SYN,
ECN
(Explicit
Congestion
Notification),
and
CWR.

Flags:
0x0c2
(SYN,
ECN,
CWR)

000.
....
....
=
Reserved:
Not
set

...0
....
....
=
Nonce:
Not
set

....
1...
....
=
Congestion
Window
Reduced
(CWR):
Set

....
.1..
....
=
ECN-‐Echo:
Set

....
..0.
....
=
Urgent:
Not
set

....
...0
....
=
Acknowledgment:
Not
set

....
....
0...
=
Push:
Not
set

....
....
.0..
=
Reset:
Not
set

....
....
..1.
=
Syn:
Set

Figure
6:

Tshark
view
of
the
flags
set
on
the
Dominate
TCP
attack
(SYN
flood)

5
By
the
time
the
reflection
attacks
reach
their
target,
the
DNS
and
NTP
source
IPs
mitigated
are
those
the

reflectors.
Since
DNS
and
NTP
reflection
attacks
make
use
of
unwitting
victims
of
DNS
resolvers
and
NTP

servers,
the
sources
themselves
cannot
be
attributed
to
a
particular
malicious
actor.
In
essence
the

attacker
pretends
to
be
any
IP
by
way
of
the
attack
scripts
ability
to
spoof
the
initial
request.

This
would

be
the
same
as
mailing
a
letter
to
someone
with
a
different
return
address
than
your
own.

Most
of
the
scripts
available,
with
the
exception
of
NTP,
share
the
same
code.

For
example,
the
UDP

based
reflection
attacks
are
similar
to
others.
As
one
the
earlier
reflection
methods,
NTP
was
originally

available
in
Perl
and
now
is
also
available
in
Python
and
C.
The
same
goes
with
TCP-‐based
attacks.

The
command
line
for
the
UDP
reflection
tools
typically
requires
a
target
IP
which
is
used
as
the
source

IP
of
the
requests.

There
is
also
a
list
of
servers,
NTP
or
DNS
in
this
case,
that
are
used
to
reflect
the

request
back
to
the
target.

DNS
Flooder
v1.3

Usage:
./dnsr13
<target
IP/hostname>
<port
to
hit>
<reflection
file
(format:
IP
DOMAIN>>
<number
threads
to
use>
<time

(optional)>

Reflection
File
Format:
<IP>[space/tab]<DOMAIN>[space/tab]<IGNORED>[space/tab]<IGNORED>...

NTP
Amp
DOS
attack
(python
version)

#usage
ntpdos.py
<target
ip>
<ntpserver
list>
<number
of
threads>
ex:
ntpdos.py
1.2.3.4
file.txt
10

Dominate
attack

Usage:
./dominate
<target
IP>
<port
to
be
flooded>
<number
threads
to
use>
<pps
limiter,
-‐1
for
no
limit>
<time>

Figure
7:
Command-‐line
options
available
for
the
three
attack
tools
leveraged

On
the
booter
site,
the
actor
launching
the
attack
would
only
need
to
enter
a
target
using
the
website's

front
end.

The
commands
are
sent
in
the
background,
making
it
easy
for
anyone
to
launch
the
attack.

The
attack
contains
no
further
evidence
to
indicate
which
site
may
have
been
leveraged
at
the
time
of

the
attacks.

5.0/
Observed
DDoS
Campaigns
/
DNS
reflection
and
amplification
attacks
are
based
on
a
well-‐known

DDoS
tool
available
on
many
booter/stresser
sites.

Specifically,
the
DNS
flooder
tool
was
covered
in
a

previous
threat
advisory
by
Akamai
SIRT.

Theses
attacks
are
effective
due
to
the
large
number
of
open

DNS
resolvers
on
the
Internet.
The
attacker
only
needs
a
list
of
these
reflectors
to
query
while

impersonating
(spoofing)
the
address
of
the
target.

5.1/
DDoS
reflection
Highlighted
Campaign
/
The
following
attack
signatures
are
examples
of
DDoS

attacks
being
leveraged
in
campaigns
against
Akamai
customers.
This
single
DDoS
attack
peaked
at
123

Gbps
and
was
mitigated
effectively
by
Akamai
infrastructure.

6

• Peak
bandwidth:
123.5
Gigabits
per
second

• Peak
packets
per
second:
14
Million
Packets
Per
Second

• Attack
Vector:

DNS
reflection
/
Amplification

• Source
port:

53

• Destination
port:
Randomized

Attack
Payload
Samples
#1:

19:26:18.660629
IP
x.x.x.x.53
>
x.x.x.x.53822:
21836|
22/0/0
RRSIG,
RRSIG,
RRSIG,
AAAA
2600:803:240::2,
DNSKEY,

DNSKEY[|domain]

19:26:18.660634
IP
x.x.x.x.53
>
x.x.x.x.24319:
21836|
22/0/0
RRSIG,
RRSIG,
AAAA
2600:803:240::2,
A
63.74.109.2,
DNSKEY,

TXT
"v=spf1
ip4:63.74.109.6
ip4:63.74.109.10
ip4:63.74.109.20
mx
a:list.xxx.gov
-‐all",
MX
xxx.xxx.gov.
5,
MX
xxx.xxx.gov.
5,

SOA,
Type51,
DNSKEY,
DNSKEY[|domain]

19:26:18.660639
IP
x.x.x.x.53
>
x.x.x.x.52837:
27374|
22/0/0
DNSKEY,
RRSIG,
RRSIG,
A
63.74.109.2,
RRSIG,
RRSIG[|domain]

19:26:18.660640
IP
x.x.x.x.53
>
x.x.x.x.62018:
33118|
20/0/1
MX
xxx.xxx.gov.
5,
MX
xxx.xxx.gov.
5,
TXT
"v=spf1

ip4:63.74.109.6
ip4:63.74.109.10
ip4:63.74.109.20
mx
a:list.xxx.gov
-‐all",
A
63.74.109.2,
AAAA
2600:803:240::2,
DNSKEY,

DNSKEY,
DNSKEY,
DNSKEY,
Type51,
RRSIG[|domain]

19:26:18.660698
IP
x.x.x.x.53
>
x.x.x.x.63128:
8458|
22/0/0
SOA,
MX
xxx.xxx.gov.
5,
MX
xxx.xxx.gov.
5,
TXT
"v=spf1

ip4:63.74.109.6
ip4:63.74.109.10
ip4:63.74.109.20
mx
a:list.xxx.gov
-‐all",
AAAA
2600:803:240::2,
DNSKEY,
DNSKEY,
DNSKEY,

A
63.74.109.2,
DNSKEY,
Type51,
RRSIG[|domain]

19:26:18.660714
IP
x.x.x.x.53
>
x.x.x.x.2071:
33118|
8/0/0
DNSKEY,
RRSIG,
RRSIG,
A
63.74.109.2,
RRSIG,
TXT
"v=spf1

ip4:63.74.109.6
ip4:63.74.109.10
ip4:63.74.109.20
mx
a:list.xxx.gov
-‐all",
RRSIG[|domain]

19:26:18.660721
IP
x.x.x.x.53
>
x.x.x.x.63739:
37916|
22/0/0
RRSIG,
RRSIG,
RRSIG,
DNSKEY,
AAAA
2600:803:240::2,
A

63.74.109.2,
TXT
"v=spf1
ip4:63.74.109.6
ip4:63.74.109.10
ip4:63.74.109.20
mx
a:list.xxx.gov
-‐all",
MX
xxx.xxx.gov.
5,
MX

xxx.xxx.gov.
5,
SOA,
Type51[|domain]

Figure
8:

Attack
payloads
during
one
of
the
largest
DDoS
campaigns
mitigated
from
this
technique

5.2/
Financial
Institutions
Targeted
/
The
financial
services
industry
has
been
a
main
target
for
this
kind

of
DNS
Amplification
attack
campaign.
One
of
the
latest
DNS
amplification
attacks
that
targeted
the

financial
industry
was
observed
Jan.
10,
2016
at
around
20:31:03
UTC.

Listed
below
are
campaign
attributes
of
the
attack
traffic
that
traversed
through
one
of
Akamai’s
DDoS

mitigation
platforms
targeting
a
financial
customer:

• Peak
bandwidth:

45.17
Gigabits
per
second

• Peak
packets
per
second:
5.2
Million
packets
per
second

• Attack
Vector:

DNS
reflection
/
Amplification

7
• Source
port:

53

• Destination
port:
Randomized

Attack
Payload
Samples
#2:

20:31:03.356115
IP
x.x.x.x.53
>
x.x.x.x.4444:
25207|
20/0/1
MX
xxx.xxx.gov.
5,
MX
xxx.xxx.gov.
5,
TXT
"v=spf1

ip4:63.74.109.6
ip4:63.74.109.10
ip4:63.74.109.20
mx
a:list.xxx.gov
-‐all",
A
63.74.109.2,
AAAA
2600:803:240::2,
DNSKEY,

DNSKEY,
DNSKEY,
DNSKEY,
Type51,
RRSIG[|domain]

20:31:03.356121
IP
x.x.x.x.53
>
x.x.x.x.55571:
13091
20/2/1
RRSIG,
RRSIG,
DNSKEY,
DNSKEY,
DNSKEY[|domain]

20:31:03.356132
IP
x.x.x.x.53
>
x.x.x.x.4444:
28475|
22/0/1
RRSIG,
RRSIG,
MX
xxx.xxx.gov.
5,
MX
xxx.xxx.gov.
5,
RRSIG,
TXT

"v=spf1
ip4:63.74.109.6
ip4:63.74.109.10
ip4:63.74.109.20
mx
a:list.
xxx.gov
-‐all",
RRSIG,
A
63.74.109.2,
RRSIG[|domain]

20:31:03.356152
IP
x.x.x.x.53
>
x.x.x.x.4444:
25067|
22/0/1
RRSIG,
RRSIG,
MX
xxx.xxx.gov.
5,
MX
xxx.xxx.gov.
5,
RRSIG,
TXT

"v=spf1
ip4:63.74.109.6
ip4:63.74.109.10
ip4:63.74.109.20
mx
a:list.
xxx.gov
-‐all",
RRSIG,
A
63.74.109.2,
RRSIG[|domain]

20:31:03.356162
IP
x.x.x.x.213.53
>
x.x.x.x.4444:
31364|
20/0/1
MX
xxx.xxx.gov.
5,
MX
xxx.xxx.gov.
5,
TXT
"v=spf1

ip4:63.74.109.6
ip4:63.74.109.10
ip4:63.74.109.20
mx
a:list.
xxx.gov
-‐all",
A
63.74.109.2,
AAAA

Figure
9:
Attack
payloads
against
one
of
our
Financial
Institution
customers
during
a
DDoS
attack

5.3/
Summary
of
attacks
by
Industry
Vertical
/
As
stated
earlier,
Akamai
SIRT
has
observed
over
400

DDoS
attack
campaigns
within
the
past
3
months,
and
these
DNS
Amplifications
have
affected
several

industries.
Figure
10
provides
distribution
by
industry
vertical
on
DDoS
campaigns
mitigated
by
Akamai.

The
Primary
targeted
industry
vertical,
Online
Gaming,
accounted
for
52.42%
of
attacks.

Figure
10:
Breakdown
by
Industry
Vertical
of
DDoS
attacks
mitigated
against
the
DNSSEC
reflection
method

8

6.0/
Recommended
Mitigation
/
Like
any
other
DDoS
Reflection
/
Amplification
attack
whose
primary

function
would
be
bandwidth
generation,
these
types
of
DDoS
attacks
can
be
mitigated
by
the

implementation
of
ACLs.
The
use
of
a
DDoS
cloud
based
mitigation
provider
such
as
the
one
provided
by

Akamai
Technologies
also
is
recommended
as
many
times
the
attack
size
will
exceed
the
total
capacity

of
the
target
infrastructure.

A
snort
rule
was
originally
published
in
the
DNS
flooder/amp
advisory.

This
rule
is
meant
for
DNS

resolvers
to
detect
if
their
server
is
being
leveraged
in
reflection
attacks.

The
instance
of
many
queries

appearing
from
the
same
source
IP
would
be
evidence
of
an
attack.

The
rule
is
looking
for
DNS
queries

of
type
ANY
with
recursion
desired
and
additional
records
settings
of
OPT41
and
UDP
payload
size
9000.

The
Domain
Name
System
(DNS)
Flooder
toolkit,
or
DNS
Flooder
v1.1,
uses
reflection
and
amplification

techniques.
This
method
allows
attackers
to
launch
powerful
distributed
denial
of
service
(DDoS)
attacks

anonymously,
with
just
a
handful
of
servers.
A
previous
threat
advisory
provided
a
detailed
analysis
of

the
DNS
Flooder
toolkit
and
recommended
techniques
for
DDoS
protection
and
DDoS
mitigation.

Below
is
a
list
of
Snort
rules
and
ACLs
to
help
organizations
mount
a
more
effective
defense.

alert
udp
$EXTERNAL_NET
any
-‐>
$HOME_NET
53
(msg:"DNS
flooder
1.1
abuse";
sid:20130115;
rev:1;

content:
"|00
ff
00
01
00
00
29
23
28|";
offset:
12;
)

Figure
11:
DNS
Flooder
snort
rule

deny
udp
any
eq
53
host
x.x.x.x
gt
1023

deny
udp
any
host
x.x.x.x
fragments

Figure
12:
Target
mitigation
using
upstream
packet
filtering

7.0/
Conclusion
/
Based
upon
the
varied
numbers
of
reflection
DDoS
attacks
launched,
malicious
actors

seem
to
be
using
DNS,
SSDP,
Chargen,
SNMP,
NTP
enabled
devices
as
their
attack
resources
more

regularly
when
performing
reflected
and
amplified
DDoS
attack
campaigns.
These
techniques
are

utilized
by
the
DDoS
for
hire
underground
market.

The
historical
use
of
reflection
and
amplification
attacks
using
open
reflector
devices
indicates
that
the

attack
method
is
not
going
away,
and
that
attackers
will
seek
more
efficient
ways
to
launch
larger

attacks
in
shorter
periods
of
time,
taking
advantage
of
wider
adoption
of
new
technologies
and

exploiting
gaps
and
weaknesses
that
develop.

9

Most
stresser
suites
offer
an
array
of
attack
types,
with
DNS
Reflection
attacks
often
being
among
the

most
common
default
options.
Stresser
suites
and
Booter
APIs
are
used
frequently
to
provide
DDoS-‐As-‐
A-‐Service,
and
underground
merchants
of
these
malicious
services
are
becoming
more
widely
available

due
to
the
technological
barrier
entry
to
DDoS
attacks
being
significantly
lowered.

Premade
crimeware
kits
that
specialize
in
making
use
of
compromised
web
servers
for
DDoS
attacks
are

leaking
into
the
public
realm
at
a
rapid
pace,
and
numerous
malicious
actors
are
making
use
of
this

publicly
circulating
code
to
create
their
own
attack
kits
and
services.

Finally,
organizations
are
reminded
to
review
the
domains
affected
by
the
attacks
outlined
in
this

advisory,
specifically
in
the
DNSSEC
section.

The
snort
rule
outlined
in
the
“Recommended
Mitigation”

section
above
can
be
useful
in
protecting
affected
organizations.

Disclaimer:
Specific
domain
names
excluding
hajjamservices.xyz
were
obfuscated
for
this
report.
Abusing
a
domain

name
system
security
extension
(DNSSEC)
configured
domain
is
levergaing
the
amplification
factor
and
is
associated

with
actors
utilizing
a
DDoS-‐for-‐hire
service
and
in
no
way
is
affiliated
to
the
organization
who
owns
the
domain
name

itself.
All
of
the
information
contained
in
this
advisory
has
been
investigated,
confirmed,
and
is
associated
with
attack

activity
that
Akamai
has
observed
and
successfully
mitigated.

2016 state of the internet threat advisory dnssec ddos amplification attacks

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