ANALYSIS OF THE ATTACK SURFACE OF WINDOWS 10 VIRTUALIZATION-BASED SECURITY
us-16-Wojtczuk-Analysis-Of-The-Attack-Surface-Of-Windows-10-Virtualization-Based-Security us-16-Wojtczuk-Analysis-Of-The-Attack-Surface-Of-Windows-10-Virtualization-Based-Security
HYPERV-V SECURITY
[Un]usual threat model • Usual model: hypervisor must be resistant to attacks coming from unprivileged, worker VMs • Without VBS, root partition is semi-trusted; it can compromise Hyper-V (no big deal) because – HvCallDisableHypervisor hypercall – Cleartext hiberfile – VTd not enabled • With VBS, the threat comes from the root partition
- Page 1 and 2: Rafal Wojtczuk rafal@bromium.com AN
- Page 3 and 4: aScopeupa • Most of this research
- Page 5 and 6: aCredential Guard architectureupa P
- Page 7 and 8: aCG scenario 1upa • Admins just e
- Page 9 and 10: aNtlmIumProtectCredentialupa • In
- Page 11 and 12: aScenario 1 propertiesupa • After
- Page 13 and 14: aCG scenario 2upa • Credential Gu
- Page 15 and 16: aScenario 2 properties • No more
- Page 17 and 18: VBS-enforced code integrity • Win
- Page 19 and 20: Mixing signed & unsigned code • C
- Page 21 and 22: Kernel HVCI and kernel exploits •
- Page 23: Kernel HVCI bypass, MS16-066
- Page 27 and 28: Root partition privileges • Acces
- Page 29 and 30: Root partition privileges • I/O p
- Page 31 and 32: Problem 1 - unfiltered MMCFG • MM
- Page 33 and 34: Problem 2 - chipset registers • S
- Page 35 and 36: S4 sleep • S4 is even more fragil
- Page 37 and 38: SMM • SMM is highly-privileged mo
- Page 39 and 40: SMM • It is well-known that SMM v
- Page 41 and 42: SMM abuse example
- Page 43 and 44: Summary • Despite its limited sco
- Page 45 and 46: Extra slides: Non-VBS-specific •
- Page 47: Other funny chipset capabilities
[Un]usual threat model<br />
• Usual model: hypervisor must be resistant to attacks<br />
coming from unprivileged, worker VMs<br />
• Without VBS, root partition is semi-trusted; it can<br />
compromise Hyper-V (no big deal) because<br />
– HvCallDisableHypervisor hypercall<br />
– Cleartext hiberfile<br />
– VTd not enabled<br />
• With VBS, the threat comes from the root partition
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