The most direct bypass is to simply flip the global flag that tells the hypervisor to enforce HVCI. Inside the kernel ( ntoskrnl.exe ), there are global variables such as g_CiOptions or g_HvlpVsmEnabled .
HVCI enforces the policy. This means memory pages can be writable (to store data) or executable (to run code), but never both at the same time. This effectively kills traditional buffer overflow attacks that attempt to inject and run shellcode in kernel space. Why Attempt an HVCI Bypass?
While the term "HVCI bypass" will continue to appear in threat intelligence reports, the vast majority of these instances will comprise clever abuses of data architecture and signed software infrastructure, rather than a failure of the hypervisor isolation itself. For organizations, ensuring that and Driver Blocklisting are natively active represents the single most effective step in neutralising modern kernel-level threats. Further Technical Exploration
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. Hvci Bypass
Because direct shellcode injection into kernel memory is blocked by the hypervisor, attackers must rely on structural logical flaws, misconfigurations, or code reuse strategies to achieve a bypass. 1. Bring Your Own Vulnerable Driver (BYOVD)
Where the standard Windows kernel, user applications, and third-party drivers execute.
Lodestone had been in the CFO’s machine for eight months. It wasn't stealing files. It wasn't encrypting drives. It was just… watching . The most direct bypass is to simply flip
HVCI is a feature of Virtualization-Based Security (VBS) in Windows 10/11 and Windows Server 2016+. It uses the Windows hypervisor to create a secure, isolated environment for code integrity checks, separate from the main operating system kernel. How HVCI Protects the Kernel
As the threat landscape continues to evolve, we can expect to see new and innovative methods for HVCI Bypass emerge. To stay ahead of these threats, vehicle manufacturers and researchers must prioritize:
: Any attempt to execute kernel-mode code or modify kernel-mode memory regions is rigorously checked. The code integrity checks ensure that only signed and approved drivers and code can execute in kernel mode. This means memory pages can be writable (to
VBS leverages hardware virtualization extensions (Intel VT-x or AMD-V) to split the operating system into distinct security domains called .
The exploit chain Brine (CVE-2020-17087 & CVE-2020-1054) used a pool overflow to achieve arbitrary write and then patched the CI flag. This was a classic logical HVCI bypass.
As techniques for bypassing or working around HVCI evolve, Microsoft continuously updates the Windows security architecture to mitigate these vectors: