Bypass - Hvci

What is HVCI?

HVCI is part of Windows' defense-in-depth approach to security, introduced to make it more difficult for attackers to exploit vulnerabilities and execute malicious code at the kernel level. It leverages hardware virtualization-based security (VBS) to enforce code integrity policies, ensuring that any code attempting to run in kernel mode is validated against a set of allow-listed, signed, and authorized binaries.

HVCI is a Windows feature that utilizes the Windows Hypervisor, also known as the Windows Subsystem for Hyper-V, to create a secure execution environment. This environment ensures the integrity of kernel-mode code, making it difficult for attackers to inject malicious code into the Windows kernel. Hvci Bypass

• Read-Only + Execute (RX): Typical for kernel code sections.
• Read-Write (RW): Data sections can be written but NEVER executed.
• No Write + No Execute (NX): Stack and heap.

Real-world implications

W^X Logic: It enforces a strict "Write XOR Execute" policy. A memory page can be writable (to load data) or executable (to run code), but never both at the same time. What is HVCI

HVCI Bypass — A Riveting Exposition

Hypervisor-protected Code Integrity (HVCI) is Microsoft's advanced defense: it uses a lightweight hypervisor to enforce that only trustworthy, verified kernel code runs. It raises the bar for attackers by isolating code integrity checks from the OS kernel itself. But where there are defenses, adversaries probe for weaknesses. An “HVCI bypass” is an attacker’s attempt to run malicious kernel code or gain persistent, privileged control despite those hypervisor-enforced protections. Read-Only + Execute (RX): Typical for kernel code sections