Bypass — Hvci

For defenders, the lesson is clear: HVCI is not a silver bullet, but it is a formidable barrier. Organizations that enable HVCI (Memory Integrity) and pair it with Defender Application Control (formerly Device Guard) raise the cost of compromise so high that many attackers will simply move to an easier target.

One of the earliest documented bypasses, , demonstrated how local users could circumvent HVCI to mark kernel-mode pages as Read, Write, and Execute (RWX) simultaneously. This served as an early warning that even foundational security features could have critical implementation flaws.

However, history shows that no security feature is absolute. Future bypasses will likely come from:

What makes these attacks particularly dangerous is that they exploit an HVCI-compliant driver—legitimately signed through WHQL or attestation—to defeat the very system designed to prevent malicious code execution. Hvci Bypass

The "Bring Your Own Vulnerable Driver" (BYOVD) technique is the most common path. Attackers load a legitimate, digitally signed driver (e.g., an old version of a hardware utility) that contains a known vulnerability, such as an arbitrary memory write.

While not a direct "break" of HVCI's hypervisor logic, loading unsigned drivers is a common goal for those seeking to bypass kernel protections.

A highly isolated environment that runs secure kernel components, including the Code Integrity module ( ci.dll ). VTL 0 cannot read or write to VTL 1 memory. 2. The W^X Enforce Principle (Write or Execute) For defenders, the lesson is clear: HVCI is

HVCI operates by creating a secure environment called Virtualization-Based Security (VBS). It utilizes a hypervisor (Hyper-V) to manage memory page permissions:

By manipulating these pointers, attackers can bypass security checks before HVCI is even fully initialized or while it relies on the integrity of the underlying hardware firmware. 3. Data-Only Attacks and ROP

Hypervisor-Protected Code Integrity (), often referred to as Memory Integrity in Windows settings, has become the cornerstone of modern Windows security. By leveraging Virtualization-Based Security (VBS) , it creates a secure, hardware-isolated environment that assumes the main kernel may be compromised. What is HVCI? This served as an early warning that even

The "Secure Kernel" (which manages HVCI) now runs in VTL1, completely separate from the normal kernel. This defeats any "disable HVCI from within the normal kernel" attack unless the attacker has a VTL0 → VTL1 exploit (a far rarer and more difficult bug class).

This directly neutralizes classic exploitation techniques like data-only modifications turning into code execution, or shellcode injection into existing kernel routines. 2. Hypervisor-Enforced Page Tables

Since HVCI focuses on code integrity, it does not prevent attacks that only manipulate data.