Virtualization securityv2
- 1. Bryan Nairn, CISSP Senior Manager, Trustworthy Computing Microsoft Corporation bryan.nairn@microsoft.com
- 2. Why should I care? Server virtualization is now a given in the majority of enterprise datacenters – source IDC The virtual server and virtual server management software market is forecast to reach a market opportunity of approximately $4.1 billion by 2014. This represents a CAGR of 13.1%. – source IDC Over 40% of production virtual machines will be less secure than their physical counterparts through 2014 – source Gartner
- 3. Virtualization powers the cloud Private Cloud Public Cloud • Mimics public cloud • Available to anyone • Benefits enterprise with a network users connection • Highly virtualized • Pay-as-you-go • Strings together IT • Multi-tenant and infrastructure into virtualized resources pools • Self-service portals
- 4. Virtualization is a good thing!
- 5. Some Common VM Security Myths “I only have to patch my host OS / Kernel” “If I protect my Host machine, it will protect my VMs.” “Virtual Hard Disk files are secure by default.” “If you expose the virtual machine, you have to expose all virtual machines and the host.” “All virtual machines can see each other.” “I don’t need Anti-Virus with Virtualization”
- 7. Virtualization Architecture- Hypervisor Primary Partition Child Partitions Virtualization Stack WMI Provider Applications VM VM Worker Service Processes Ring 3 MinWin Virtualization Virtualization Service Service Providers Clients Windows (VSPs) (VSCs) Guest OS Kernel IHV Kernel Drivers VMBus VMBus Enlightenments Ring 0 Windows hypervisor Ring “-1” Server Hardware
- 8. Hypervisor Security Assumptions Guests are untrusted Trust relationships Parent must be trusted by hypervisor Parent must be trusted by children Hypercall interface will be well documented and widely available to attackers All hypercalls can be attempted by guests Can detect you are running on a hypervisor + version The internal design of the hypervisor will be well understood
- 9. Hypervisor Security Goals Strong isolation between partitions Protect confidentiality and integrity of guest data Separation Unique hypervisor resource pools per guest Separate worker processes per guest Guest-to-parent communications over unique channels Non-interference Guests cannot affect the contents of other guests, parent, hypervisor Guest computations protected from other guests Guest-to-guest communications not allowed through VM interfaces
- 10. Hyper-V Isolation No sharing of virtualized devices Separate VMBus per VM to the parent No sharing of memory Each has its own address space VMs cannot communicate with each other, except through traditional networking Guests can’t perform DMA attacks because they’re never mapped to physical devices Guests cannot write to the hypervisor Parent partition cannot write to the hypervisor
- 11. Hyper-V Security Hardening Hypervisor has separate address space Guest addresses != Hypervisor addresses No 3rd party code in the Hypervisor Limited number of channels from guests to hypervisor No “IOCTL”-like things Guest to guest communication through hypervisor is prohibited No shared memory mapped between guests Guests never touch real hardware I/O
- 12. Hyper-V Security Model Uses Authorization Manager (AzMan) Fine grained authorization and access control Department and role based Segregate who can manage groups of VMs Define specific functions for individuals or roles Start, stop, create, add hardware, change drive image VM administrators don’t have to be Server 2008 administrators Guest resources are controlled by per VM configuration files Shared resources are protected Read-only (CD ISO file) Copy on write (differencing disks)
- 13. Virtualization Attack Vectors Host Hardware Virtual Machine Host OS Virtual Machine Hard Disk Files Virtual Machine Configuration Files Remote Management/Control interfaces Guest Operating System Virtual Networks
- 14. Common Attacks: Host Host Compromise for Deployment, Duplication and Deletion Control of Virtual Machines Direct Code / File injection to Virtualization File Structure Virtual Hard Disks Virtual Configuration Files Time Sync Hardware Rootkits / Malware Drivers (Attack Surface / Stability)
- 15. It’s all about the what’s underneath…
- 16. Use Remote Management All Virtualization Solutions include some form of remote control. Access to these tools should be limited. Limit scope of access / control Protect the remote control mechanisms! Use limited use accounts for control Make sure the connections are encrypted / authenticated (SSL, RDP over SSL) Use logging VM VM VM VM VM VMVM VM VM VM VMVM VM VM VM VM VM V VMVM VM VM VM VM M
- 17. File Types and Locations .vhd disk file – In folder you specify in settings .vhdd disk file – In folder you specify in settings .vud disk file – In vmc-file folder .vsv disk file – In vmc-file folder
- 18. Common Attacks: Guest Unpatched Virtual Machines Older Operating Systems Test or Development machines (these often are not managed in the same way as production machines) Un-managed or user deployed virtual machines Backups and archives
- 19. Guest Attacks The Virtualization File Structure Virtual Hard Disks File / Code Injection Can be Directly Mounted / accessed Virtual Configuration Files Base Configuration changes Redirection / addition of Virtual drives / Resoures BIOS <hardware> <memory> <ram_size type="integer">256</ram_size> </memory> ... <pci_bus> <ethernet_adapter> <controller_count type="integer">2</controller_count> </ethernet_adapter> </pci_bus> </hardware>
- 20. VHD Redirection
- 21. Threat Landscape: Virtualized Attackers? Is this is one of the next big attack vectors on the horizon? The VM industry is focused on securing the VMs from attack. Very little thought of VMs being used as the attacker. Cases are starting to appear where people use VMs to attack, then shutdown the VM to remove any trace of evidence.
- 22. Threat Landscape: Virtualized Attackers? But we do write all events to the SysLog Things that go into drive slack are recoverable using forensics tools We still have network traces… …and audit logs …and firewall and router logs …not to mention video cameras in the server room.
- 24. Host Attacks: Potential Solutions Harden the Host Servers Where a Hypervisor or Specialist Kernel is used, the Host attack surface is smaller, however updating and patching is still required. Use single role servers and remove unwanted and un-necessary services / attack vectors Use a local firewall and only allow limited host control / management ports over encrypted and authenticated channels. Use limited scope admin accounts with strong passwords Protect the Virtual Machine files Access Control Lists (limited to the security context for the users who manage them and the services that control them. Encryption Disk / Volume / Folder / File Auditing file access, creation, deletion … Don’t forget the backup files / archives
- 25. Guest Attacks: Potential Solutions Harden the Guest Operating Systems Treat the guest OS as if it was a physical machine Isolate the machine with Virtual Networks / VLANs Local Only Access NAT Segmented networks IPSec Isolation Physical Isolation (Separate NICs)
- 26. Use Access Control Lists Deny Read-only Read/Write • Cannot modify VMC file • See the VM in web • See the VM in web • Will not appear in web console and VRMC console and VMRC console or VMRC • Can interact with VM • Can interact with the VM • Cannot start, stop, pause • Can or resume VMs start, stop, pause, resume VMs
- 27. Deployment Considerations Minimize risk to the Parent Partition Use Server Core Don’t run arbitrary apps, no web surfing Run your apps and services in guests Moving VMs from Virtual Server to Hyper-V FIRST: Uninstall the VM Additions Two physical network adapters at minimum One for management (use a VLAN too) One (or more) for vm networking Dedicated iSCSI Connect to back-end management network Only expose guests to internet traffic
- 28. Anti-Virus & BitLocker… Parent partition Run AV software and exclude .vhd Child partitions Run AV software within each VM BitLocker Great for branch office Can be used within a VM http://blogs.technet.com/virtualworld/archive/2008/02/16/using- bitlocker-under-virtual-pc-virtual-server.aspx
- 29. Conclusions Reduce the attack surface on the Host Use least privilege access Audit the deployment, maintenance, control and access to virtual machines Leverage backups, snapshots and redundancy to reduce impact of Host / Guest maintenance Secure your Virtual Machine Hard Disk and configuration files, including backups and archives Use Virtual Networks / VLANs / IPSec to Isolate machines, especially before they are exposed to the network.
- 30. Resources Step-by-Step Guide to Getting Started with Hyper-V http://technet2.microsoft.com/windowsserver2008/en/library/c513e254- adf1-400e-8fcb-c1aec8a029311033.mspx?mfr=true Virtualization Team Blog http://blogs.technet.com/virtualization Microsoft Virtualization Website http://www.microsoft.com/virtualization Using BitLocker under Virtual PC / Virtual Server http://blogs.technet.com/virtualworld/archive/2008/02/16/using-bitlocker- under-virtual-pc-virtual-server.aspx
- 31. We would all rather be doing something else..
Editor's Notes
- #3: The growth we’ve seen in virtualization over the last 5-10 years is quite amazing. Despite the economic crisis of 2008 and the down-turn in the economy, as well as IT spending, we’re still seeing growth. POINT #1In fact, virtualization has matured enough that we’re now seeing a shift to virtual clients, as well as heavy growth in virtualization management tools. Not counting client virtualization…POINT #2The key take away from this slide is that virtualization is still growing. Moreover, we see a lot of insecurity due to the introduction of new technologies and its added complexity. POINT #3We can expect to see this number decline as virtual server and configuration management tools mature.
- #4: Why do other people care? Virtualization powers the cloud. The speed at which cloud services, whether public or private, are adopted, depends, in large part, on the security, privacy and reliability of said services. Virtualization security plays a significant part in this equation. Although the focus of this presentation isn’t on cloud architecture, it’s important to mention that both the public and private iterations rely heavily on virtualization. The private cloud virtualizing resources for applications in the enterpriseThe public cloud providing multi-tenancy for user and/or company environments
- #5: When securely architected, deployed and managed, virtualization is great!It provides for service flexibility, as well as scalability of applications and services, not to mention it requires less rackspace and generally consumes less power.
- #6: In the cloud – there is a big difference between Azure (base template which is patched) or Amazon where you are responsible for your VMDon’t assume that in a cloud based scenario that your service provider has you covered by patching. It’s all different.Azure – standard image (check box – auto install base image updates)Amazon world – patch base images – do not patch deployed imagesVM needs to be treated as a stand alone machine. Firewall rules applyNo encryption built in- if someone has your
- #7: In computer science, hierarchical protection domains,[1][2] often called protection rings, are a mechanism to protect data and functionality from faults (fault tolerance) and malicious behaviour (computer security). This approach is diametrically opposite to that of capability-based security.Computer operating systems provide different levels of access to resources. A protection ring is one of two or more hierarchical levels or layers of privilege within the architecture of a computer system. This is generally hardware-enforced by some CPUarchitectures that provide different CPU modes at the hardware or microcodelevel. Rings are arranged in a hierarchy from most privileged (most trusted, usually numbered zero) to least privileged (least trusted, usually with the highest ring number). On most operating systems, Ring 0 is the level with the most privileges and interacts most directly with the physical hardware such as the CPU and memory.Recent CPUs from Intel and AMD offer x86 virtualization instructions for a hypervisor to control Ring 0 hardware access. Although they are mutually incompatible, both Intel VT-x (codenamed "Vanderpool") and AMD-V (codenamed "Pacifica") create a new "Ring -1" so that a guest operating system can run Ring 0 operations natively without affecting other guests or the host OS.[10]
- #9: Imagine you’re living in a house and renting out rooms. You can’t trust your guests or boarders. You can trust in the integrity of your house and your guests need to place an inherent amount of trust in you.Now imagine you have something valuable in your house. Something a thief would want. Given the value of the dollar these days, let’s say that you have hundreds of gold bars inside your house. My like a hypervisor, you can guarantee there is publicly available information about your house. Anyone can knock on your door. Anyone can inspect your windows, doors and locks to ascertain versions. All of these things are can be well understood. The point? When it comes to your hypervisor. Don’t trust anything.
- #17: Still biggest attack vectorIf I can deploy my own virtual server, you win.Access should be limited by firewall rulesRBAC should be baked into the tool.