Microsoft security researchers have uncovered four critical vulnerabilities in Windows BitLocker that could allow attackers with physical access to bypass the encryption system and extract sensitive data.
The findings, revealed in research dubbed “BitUnlocker,” demonstrate sophisticated attack methods targeting the Windows Recovery Environment (WinRE) to circumvent Microsoft’s flagship data protection technology.
Security Flaws Target Windows Recovery Environment
The vulnerabilities, discovered by Alon Leviev and Netanel Ben Simon from Microsoft’s Offensive Research & Security Engineering (MORSE) team, exploit weaknesses in how WinRE processes external files and configurations.
The researchers identified four distinct attack vectors that allow unauthorized access to BitLocker-protected systems:
- CVE-2025-48800 enables attackers to bypass WIM (Windows Imaging Format) validation by manipulating the Boot.sdi file’s offset pointer, causing the system to boot an untrusted recovery environment while validating a trusted one.
- CVE-2025-48003 exploits ReAgent.xml parsing to schedule malicious operations, including launching tttracer.exe to execute command prompts with full system access.
- CVE-2025-48804 leverages WinRE app trust validation by utilizing the pre-registered SetupPlatform.exe to gain persistent command-line access through keyboard shortcuts.
- CVE-2025-48818 targets BCD (Boot Configuration Data) parsing to redirect WinRE’s target OS location, enabling Push Button Reset exploitation to decrypt BitLocker volumes.
The research reveals that WinRE, designed as a recovery platform for critical system issues, inadvertently creates an attack surface when parsing configuration files from unprotected volumes.
Attackers can manipulate these external files to gain elevated privileges and access encrypted data without triggering BitLocker’s standard protection mechanisms.
Microsoft Responds with July 2025 Security Patches
Microsoft addressed all four vulnerabilities as part of its July 2025 Patch Tuesday release, issuing comprehensive security updates across affected Windows versions.
The patches target Windows 10 (versions 1607, 21H2, 22H2), Windows 11 (versions 22H2, 23H2, 24H2), and Windows Server editions (2016, 2022, 2025).
Security updates KB5062552, KB5062553, KB5062554, and KB5062560 specifically address the BitLocker vulnerabilities, with organizations urged to prioritize immediate deployment.
The vulnerabilities carry CVSS scores ranging from 6.8 to 8.1, with Microsoft assessing exploitation as “more likely” for several of the flaws.
The research team’s findings were scheduled for presentation at Black Hat USA 2025 in Las Vegas, highlighting the significance of the discoveries within the cybersecurity community.
The presentation, titled “BitUnlocker: Leveraging Windows Recovery to Extract BitLocker Secrets,” demonstrates the researchers’ comprehensive analysis of WinRE’s security architecture and attack methodologies.
Enhanced Protection Strategies and Industry Impact
Beyond applying the security patches, Microsoft recommends implementing additional BitLocker countermeasures to strengthen protection against physical attacks.
Organizations should enable TPM+PIN for pre-boot authentication, which adds an additional authentication layer before the system boots, significantly reducing the risk of physical bypass attempts.
Microsoft also advises enabling the REVISE mitigation for anti-rollback protection, which prevents attackers from downgrading to vulnerable system states.
These enhanced protections work in conjunction with the security patches to provide comprehensive defense against the identified attack vectors.
The discoveries underscore the importance of defense-in-depth strategies for data protection, particularly in scenarios involving physical device access.
While BitLocker remains a robust encryption solution, the research demonstrates that even sophisticated security systems require continuous evaluation and improvement to address emerging threat vectors.
The BitUnlocker research represents a significant contribution to understanding encryption bypass techniques and reinforces the critical role of internal security research teams in identifying and addressing vulnerabilities before they can be exploited maliciously.
Organizations relying on BitLocker for data protection should prioritize applying the July 2025 security updates while implementing the recommended additional security measures to maintain robust protection against physical attacks.
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