CVE-2024-20665 is a security vulnerability identified in Microsoft Windows 10 Version 1809, specifically affecting the BitLocker encryption feature. The vulnerability is classified under CWE-693, which relates to Protection Mechanism Failure. BitLocker is a full disk encryption technology designed to protect data by providing encryption for entire volumes. This vulnerability allows an attacker with high privileges and requiring user interaction to bypass BitLocker's security protections, potentially compromising the confidentiality, integrity, and availability of encrypted data. The CVSS 3.1 base score is 6.1 (medium severity), with an attack vector of physical (AV:P), low attack complexity (AC:L), requiring high privileges (PR:H), and user interaction (UI:R). The scope is unchanged (S:U), meaning the impact is limited to the vulnerable component. The vulnerability can lead to high impact on confidentiality, integrity, and availability (C:H/I:H/A:H), indicating that successful exploitation could allow an attacker to decrypt or manipulate protected data, or disrupt access to it. No known exploits are reported in the wild as of the publication date (April 9, 2024), and no patches have been linked yet. The vulnerability was reserved in late 2023 and is now publicly disclosed. The lack of a patch means that affected systems remain at risk until remediation is available. This vulnerability is particularly critical for environments relying on BitLocker for data protection, especially where physical access to devices is possible, as the attack vector is physical. The requirement for high privileges and user interaction suggests that exploitation is not trivial but feasible in targeted scenarios, such as insider threats or sophisticated attackers with some level of access.

For European organizations, the impact of CVE-2024-20665 can be significant, especially for sectors handling sensitive or regulated data such as finance, healthcare, government, and critical infrastructure. BitLocker is widely used in enterprise environments across Europe to comply with data protection regulations like GDPR, which mandates strong data security controls. A bypass of BitLocker protections could lead to unauthorized data disclosure, data tampering, or denial of access to encrypted data, resulting in regulatory penalties, reputational damage, and operational disruption. Organizations with remote or mobile workforces are particularly vulnerable due to the increased risk of physical device access by unauthorized individuals. The medium severity rating and the need for high privileges and user interaction mean that while widespread automated exploitation is unlikely, targeted attacks against high-value assets or insider threats could leverage this vulnerability effectively. The absence of known exploits in the wild currently reduces immediate risk but does not eliminate it, especially as threat actors may develop exploits over time.

1. Immediate mitigation should focus on minimizing physical access to devices running Windows 10 Version 1809 with BitLocker enabled. Implement strict physical security controls, including secure storage and access logging. 2. Enforce strict user privilege management to limit the number of users with high-level privileges, reducing the attack surface. 3. Educate users about the risks of social engineering and the importance of avoiding suspicious interactions that could trigger exploitation. 4. Monitor systems for unusual activity indicative of privilege escalation or attempts to bypass BitLocker protections. 5. Plan and prioritize upgrading affected systems to newer, supported Windows versions where this vulnerability is patched or mitigated. 6. Regularly review and apply security updates from Microsoft as soon as they become available for this vulnerability. 7. Employ complementary security controls such as hardware security modules (TPM) and multifactor authentication to strengthen device security. 8. Conduct regular security audits and penetration testing focused on encryption and access controls to detect potential weaknesses.