Hvci Bypass [verified] | Authentic

An interesting feature of HVCI Bypass is the move toward "Hypervisor-on-Hypervisor"

If the race is won, the CPU executes code from a page the hypervisor believed was data. This is highly timing-dependent and notoriously unreliable, but on single-core VMs or systems with weak hypervisor scheduling, it is plausible. Hvci Bypass

Understanding HVCI Bypasses: Mechanisms and Vulnerabilities An interesting feature of HVCI Bypass is the

$$E = mc^2$$

The Theory:

If an attacker achieves arbitrary kernel read/write (via a vulnerable driver), they can patch g_CiOptions from 0x10 (HVCI enabled) to 0x00 (disabled) or modify Microsoft_Windows_HyperV_KernelCodeIntegrity_Enable flags. Vulnerability: A pool overflow in the Windows Kernel

Understanding HVCI Bypass: Security, Methods, and the Battle for Kernel Integrity

• Vulnerability: A pool overflow in the Windows Kernel Streaming service (ks.sys).
• Bypass method: After overflowing into a neighboring pool chunk, the exploit (combined with CVE-2020-1054) performed a variable overwrite of g_CiOptions.
• Impact: The first public, reliable HVCI bypass in the wild. Used by the Buer loader and Trickbot.
• Patch: Microsoft hardened the variable location and added hypervisor enforcement.