CVE-2025-59284 is a vulnerability classified under CWE-200 (Exposure of Sensitive Information) affecting Microsoft Windows 11 version 22H2 (build 10.0.22621.0). The flaw resides in the Windows NTLM authentication protocol implementation, where an unauthorized local attacker can exploit the vulnerability to perform spoofing attacks. This spoofing could allow the attacker to access sensitive information that should otherwise be protected. The vulnerability requires local access and user interaction, meaning the attacker must have some level of presence on the machine and trick a user into performing an action. The CVSS v3.1 base score is 3.3, indicating low severity, primarily due to the limited attack vector (local), no privileges required, and the need for user interaction. The vulnerability does not affect system integrity or availability, focusing solely on confidentiality. No known exploits have been reported in the wild, and no patches have been published at the time of this report. The exposure of sensitive information through NTLM spoofing could be leveraged in lateral movement or reconnaissance phases of an attack, especially in environments where NTLM is still widely used for authentication. Given the persistence of NTLM in many enterprise networks, this vulnerability could be a foothold for attackers to gather information for further exploitation.

For European organizations, the primary impact of CVE-2025-59284 is the potential unauthorized disclosure of sensitive information within local environments using Windows 11 22H2. This could facilitate further attacks such as lateral movement or privilege escalation if attackers gather enough data to craft more sophisticated exploits. Organizations relying heavily on NTLM authentication, especially in legacy or mixed environments, are at greater risk. Although the vulnerability does not directly compromise system integrity or availability, the confidentiality breach could expose user credentials or session information, undermining trust in internal network security. This is particularly critical for sectors handling sensitive personal data or intellectual property, such as finance, healthcare, and government. The requirement for local access and user interaction limits the scope but does not eliminate risk, especially in environments with many users or shared workstations. The absence of known exploits reduces immediate threat but does not preclude future exploitation once details become widely known.

To mitigate CVE-2025-59284, European organizations should prioritize reducing reliance on NTLM authentication by transitioning to more secure protocols like Kerberos or implementing NTLM blocking policies where feasible. Network segmentation should be enforced to limit local attacker movement and exposure. Endpoint detection and response (EDR) solutions should be configured to monitor for unusual local spoofing or authentication anomalies. User education is important to reduce risky interactions that could trigger the vulnerability. Applying the latest Windows updates as soon as Microsoft releases patches is critical. Additionally, organizations should audit and restrict local user privileges to minimize the potential for unauthorized local access. Employing multi-factor authentication (MFA) can also reduce the impact of credential exposure. Regularly reviewing and hardening group policies related to authentication protocols will further reduce attack surface. Finally, monitoring network traffic for NTLM usage and suspicious activity can help detect exploitation attempts early.