The Windows 8.1 Kernel Patch Protection
Summary: Cisco Talos analyzed how the Uroburos kernel-mode rootkit, which targets Windows 7 64-bit, disables Kernel Patch Protection (Patchguard v7) without touching KeBugCheckEx directly, instead forging the RtlCaptureContext routine and registering a custom software interrupt 0x3C to intercept Patchguard's CRITICAL_STRUCTURE_CORRUPTION crash request. The post then describes Patchguard v8 on Windows 8.1, whose initialization routine (about 95 KB of machine code in the kernel INIT section) builds an encrypted, repeatedly relocated buffer in nonpaged pool and self-verifies its own code, which the author says renders the older bypass techniques obsolete.
Key Takeaway: A rootkit that can silently disarm kernel patch protection on Windows 7 has no working equivalent against Windows 8.1, but the author states he will demonstrate at an upcoming conference that a skilled researcher can still disarm Patchguard v8 and even reuse Microsoft's own Patchguard code to protect attacker hooks.
Read the original at Cisco Talos ↗
- Topics
- Zero-Days & Exploits
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