CVE-1999-0787 is a vulnerability identified in version 1.2.27 of the SSH (Secure Shell) software, specifically related to the SSH authentication agent's handling of UNIX domain sockets. The vulnerability arises because the SSH authentication agent follows symbolic links (symlinks) when accessing UNIX domain sockets. This behavior can be exploited by an attacker with local access to the system to redirect the authentication agent's socket communications to arbitrary locations. By leveraging this, an attacker could potentially interfere with or manipulate the authentication process, leading to partial integrity compromise. However, the vulnerability does not impact confidentiality or availability directly, and no authentication is required to exploit it. The CVSS score of 2.1 (low severity) reflects the limited impact and the requirement for local access. Since this vulnerability dates back to 1999 and affects an outdated SSH version (1.2.27), modern SSH implementations have long since addressed this issue. No patches are listed for this specific version, and there are no known exploits in the wild. The vulnerability primarily concerns systems still running this legacy SSH version, which is rare in contemporary environments.

For European organizations, the impact of CVE-1999-0787 is minimal in modern contexts because the affected SSH version (1.2.27) is obsolete and unlikely to be in active use. However, if legacy systems or embedded devices running this old SSH version remain in operation, there is a risk that local attackers could exploit the symlink-following behavior to manipulate authentication agent communications. This could lead to unauthorized actions or privilege escalation within the affected system, compromising system integrity. Given that the vulnerability requires local access and does not affect confidentiality or availability, the overall risk to European organizations is low. Nonetheless, organizations with legacy infrastructure should be aware of this vulnerability as part of their risk assessments and ensure that outdated SSH versions are upgraded or isolated to prevent exploitation.

1. Upgrade SSH software to a modern, supported version that no longer exhibits this vulnerability. Versions postdating 1.2.27 have addressed this issue. 2. Audit and identify any legacy systems or embedded devices still running SSH 1.2.27 or similarly outdated versions; plan for their upgrade or decommissioning. 3. Restrict local access to critical systems by enforcing strict access controls and monitoring to prevent unauthorized users from gaining the local presence needed to exploit this vulnerability. 4. Employ filesystem integrity monitoring to detect unauthorized creation or manipulation of symlinks and UNIX domain sockets. 5. Where upgrading is not immediately feasible, consider isolating vulnerable systems within segmented network zones with limited user access to reduce attack surface. 6. Regularly review and update security policies to ensure legacy software vulnerabilities are accounted for in risk management.