CVE-1999-1452 is a vulnerability found in the Graphical Identification and Authentication (GINA) component of Microsoft Windows NT 4.0. GINA is responsible for handling secure user authentication and interactive logon processes. This specific vulnerability allows an attacker with physical access to a locked workstation to extract a portion of the clipboard contents from the user who locked the system. The attack is performed by pasting (using CTRL-V) clipboard data directly into the username prompt on the locked screen, thereby revealing sensitive clipboard information without requiring authentication. This vulnerability does not allow modification or compromise of system integrity or availability, but it does expose potentially sensitive data that was copied to the clipboard prior to locking the workstation. The vulnerability is local access only (AV:L), requires low attack complexity (AC:L), does not require authentication (Au:N), and impacts confidentiality (C:P) but not integrity or availability. It was published in 1999 and affects only Windows NT 4.0, an operating system that is now obsolete and unsupported. No patches are available, and no known exploits have been reported in the wild. The CVSS score is low (2.1), reflecting the limited scope and impact of this vulnerability.

For European organizations, the impact of CVE-1999-1452 is minimal in modern contexts because Windows NT 4.0 is an outdated operating system no longer in active use or supported. However, in rare cases where legacy systems running Windows NT 4.0 remain operational—such as in industrial control systems, legacy financial systems, or archival environments—this vulnerability could lead to unauthorized disclosure of sensitive clipboard data if an attacker gains physical access. This could potentially expose passwords, cryptographic keys, or confidential information copied to the clipboard before locking the workstation. While the confidentiality impact is limited and does not affect system integrity or availability, any data leakage in regulated environments (e.g., GDPR governed entities) could have compliance implications. The requirement for physical access significantly reduces the likelihood of exploitation in most corporate environments, especially those with strong physical security controls.

Given the absence of patches and the obsolescence of Windows NT 4.0, the primary mitigation is to phase out and replace legacy Windows NT 4.0 systems with modern, supported operating systems that have improved security models and ongoing vendor support. For environments where legacy systems must remain operational, strict physical security controls should be enforced to prevent unauthorized physical access to workstations. Additionally, users should be trained to clear sensitive data from the clipboard before locking their workstations or to avoid copying sensitive information to the clipboard altogether. Implementing full disk encryption and session timeout policies can further reduce risks. Network segmentation and monitoring can help isolate legacy systems to minimize exposure. Finally, organizations should conduct audits to identify any remaining Windows NT 4.0 systems and prioritize their upgrade or decommissioning.