Security researchers disclosed an evasion technique that bypasses Windows Driver Signature Enforcement (DSE) by weaponizing OS component downgrades against fully patched Windows 10, Windows 11, and Windows Server systems. The attack leverages flaws in the Windows Update architecture (CVE-2024-21302 and CVE-2024-38202) alongside the “ItsNotASecurityBoundary” technique. By manipulating update staging directories, an attacker with administrative privileges forces the operating system to replace Code Integrity binaries (ci.dll) with older, vulnerable versions without invalidating patch status or triggering System File Checker (sfc.exe) alerts.

Once ci.dll is downgraded to a build vulnerable to False File Immutability (FFI) race conditions, catalog validation routines can be tricked into accepting forged authentihashes during memory-mapped reads. This primitive enables adversaries to bypass DSE without third-party vulnerable drivers (BYOVD), allowing them to load unsigned kernel-mode drivers, neutralize endpoint detection and response (EDR) hooks, and install Ring 0 rootkits. Microsoft issued patches addressing specific downgrade vectors, but researchers released the “Windows Downdate” tool to demonstrate persistent architectural exposure.

Why it matters:

• Bullet 1 — Technical & Architecture Risk: Downgrading Code Integrity binaries subverts Driver Signature Enforcement internally, turning fixed flaws into functional zero-days and allowing stealthy Ring 0 execution without tripping Microsoft Vulnerable Driver Blocklists.
• Bullet 2 — Strategic & Defender Imperative: Defenders must enforce Virtualization-Based Security (VBS) with mandatory HVCI, restrict local administrator rights to block servicing tampering, and monitor file modifications within the Windows Update component store.