A significant security flaw, identified as CVE-2025-48818, has been discovered in Windows BitLocker, allowing attackers with physical access to bypass the encryption feature. This vulnerability, rated with a CVSS score of 6.8, affects multiple versions of Windows, including Windows 10, Windows 11, and various Windows Server editions.
Understanding CVE-2025-48818
CVE-2025-48818 is a time-of-check time-of-use (TOCTOU) race condition vulnerability. In such vulnerabilities, there’s a critical time gap between the system’s security verification and the actual use of a resource. Attackers can exploit this gap to gain unauthorized access. In this case, the flaw specifically targets BitLocker Device Encryption, Microsoft’s full-disk encryption solution designed to protect data at rest.
Attack Methodology
To exploit this vulnerability, an attacker needs physical access to the target system. The attack does not require any user interaction or prior authentication. By manipulating the timing during the BitLocker authentication process, the attacker can bypass security controls and access encrypted data. This could lead to the exposure of sensitive information, including user credentials, corporate data, and system configurations.
Affected Systems
The vulnerability impacts a wide range of Windows platforms, including:
– Windows 10 (versions 1607, 21H2, 22H2)
– Windows 11 (versions 22H2, 23H2, 24H2)
– Windows Server editions (2016, 2022, 2025)
It affects all architectures (32-bit, x64, ARM64) and both standard and Server Core installations.
Microsoft’s Response
In response to this critical vulnerability, Microsoft has released security updates to address the issue. The patches include specific build numbers:
– Windows 10 22H2 (10.0.19045.6093)
– Windows 11 23H2 (10.0.22631.5624)
– Windows Server 2025 (10.0.26100.4652)
Organizations and individual users are strongly advised to apply these updates immediately through their standard patch management processes to mitigate the risk associated with this vulnerability.
Mitigation Strategies
Beyond applying the necessary patches, users and administrators should consider the following measures to enhance security:
1. Enable Pre-Boot Authentication: Configuring BitLocker with a pre-boot PIN ensures that encryption keys are not automatically released without user interaction, adding an extra layer of security.
2. Restrict Physical Access: Implementing strict physical security controls can prevent unauthorized individuals from gaining access to devices.
3. Regular Security Audits: Conducting periodic security assessments can help identify and address potential vulnerabilities before they can be exploited.
Conclusion
The discovery of CVE-2025-48818 underscores the importance of maintaining up-to-date security measures and being vigilant about potential vulnerabilities. By promptly applying Microsoft’s patches and implementing additional security practices, users can protect their sensitive data from potential threats.
