Windows BitLocker Bypass Vulnerability Let Attackers Bypass Security Feature

A critical security vulnerability in Windows BitLocker enables attackers to bypass the encryption feature through a sophisticated time-of-check time-of-use (TOCTOU) race condition attack. 

Designated as CVE-2025-48818, this vulnerability affects multiple Windows versions and carries an Important severity rating with a CVSS score of 6.8. 

The flaw allows unauthorized attackers with physical access to circumvent BitLocker Device Encryption, potentially exposing sensitive encrypted data on target systems.

Key Takeaways
1. CVE-2025-48818: TOCTOU race condition bypasses BitLocker encryption (CVSS 6.8).
2. Requires direct system access, not remote exploitation.
3. Affects Windows 10, 11, and Server editions.
4. Microsoft issued specific patches (KB5062552, KB5062553, KB5062554, KB5062560) available for immediate deployment.

BitLocker’s TOCTOU Flaw (CVE-2025-48818)

CVE-2025-48818 represents a time-of-check time-of-use race condition classified under CWE-367, which exploits the temporal gap between security verification and resource utilization. 

The vulnerability specifically targets the BitLocker Device Encryption feature, Microsoft‘s full-disk encryption solution designed to protect data at rest. 

The attack vector requires physical access (AV:P) to the target system, with low attack complexity (AC:L) and no user interaction required (UI:N).

The CVSS 3.1 vector string CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C indicates high impact on confidentiality, integrity, and availability components. 

The vulnerability was discovered by security researchers Alon Leviev and Netanel Ben Simon from Microsoft’s Offensive Research & Security Engineering (MORSE) team, highlighting the importance of internal security research initiatives.

The exploitation of this vulnerability allows attackers to bypass BitLocker Device Encryption on system storage devices, effectively negating the protection offered by full-disk encryption. 

An attacker with physical access can exploit the race condition to gain unauthorized access to encrypted data, potentially compromising sensitive information, including user credentials, corporate data, and system configurations.

The attack methodology leverages the inherent timing vulnerabilities in the BitLocker authentication process, where the system checks encryption status and subsequently grants access to encrypted volumes. 

During this critical window, an attacker can manipulate the authentication sequence to bypass security controls. 

The vulnerability affects a comprehensive range of Windows platforms, including Windows 10 (versions 1607, 21H2, 22H2), Windows 11 (versions 22H2, 23H2, 24H2), and Windows Server editions (2016, 2022, 2025).

Risk Factors	Details
Affected Products	– Windows 10 (all versions: 1607, 21H2, 22H2)- Windows 11 (versions 22H2, 23H2, 24H2)- Windows Server 2016, 2022, 2025- All architectures: 32-bit, x64, ARM64- Both standard and Server Core installations
Impact	Security Feature Bypass
Exploit Prerequisites	Direct access to target system required,No authentication needed,No User Interaction
CVSS 3.1 Score	6.8 (Medium)

Mitigation Strategies

Microsoft has released comprehensive security updates across all affected Windows versions to address CVE-2025-48818. 

The patches include specific build numbers: Windows 10 22H2 (10.0.19045.6093), Windows 11 23H2 (10.0.22631.5624), and Windows Server 2025 (10.0.26100.4652). Organizations should immediately apply these updates through their standard patch management processes.

System administrators should prioritize the installation of security updates KB5062552, KB5062553, KB5062554, and KB5062560, depending on their specific Windows version. 

Additionally, organizations should implement physical security controls to limit unauthorized access to BitLocker-protected systems, as the vulnerability requires physical proximity to the target device. 

Regular security audits and monitoring for unauthorized access attempts can provide additional layers of protection while the patches are being deployed across enterprise environments.

MSSP Pricing Guide: How to Cut Through the Noise and the Hidden Cost-> Get Your Free Guide