CVE-1999-0864 is a high-severity local privilege escalation vulnerability affecting UnixWare versions 7.0, 7.0.1, 7.1, and 7.1.1, products developed by SCO. The vulnerability arises from the way UnixWare programs handle core dump files. Specifically, when a program crashes and generates a core dump, it creates a file named ./core.pid. A local attacker can exploit this by creating a symbolic link (symlink) named ./core.pid that points to an arbitrary file. When the vulnerable program writes the core dump, it inadvertently overwrites or modifies the target file pointed to by the symlink. This symlink attack allows a local user to modify files they normally would not have permission to alter, potentially leading to unauthorized changes in system files or configuration data. The vulnerability requires local access, does not require authentication (as the attacker is already a local user), and can compromise confidentiality, integrity, and availability of the affected system. The CVSS v2 score is 7.2, reflecting a high impact with low attack complexity and no authentication required. No patches are available for this vulnerability, and there are no known exploits in the wild, likely due to the age of the vulnerability and the declining use of UnixWare systems. However, the fundamental flaw in core dump handling remains a critical security concern for any remaining UnixWare deployments.

For European organizations still operating UnixWare systems, this vulnerability poses a significant risk. A local attacker, such as a disgruntled employee or someone who gains limited local access, could exploit this flaw to modify critical system files, escalate privileges, or disrupt services. This could lead to unauthorized data disclosure, system compromise, or denial of service. Given that UnixWare is a niche legacy operating system, the impact is mostly relevant to organizations in sectors that rely on legacy UnixWare infrastructure, such as certain industrial control systems, telecommunications, or specialized financial services. The vulnerability undermines system integrity and availability, potentially affecting business continuity and compliance with data protection regulations like GDPR if sensitive data is exposed or systems are disrupted.

Since no official patch is available, mitigation must focus on reducing the attack surface and limiting local user capabilities. Organizations should: 1) Restrict local user access strictly to trusted personnel and enforce the principle of least privilege to prevent unauthorized local logins. 2) Disable core dumps for critical applications or system-wide by configuring system parameters (e.g., using 'ulimit -c 0') to prevent core file generation, thereby eliminating the attack vector. 3) Monitor and audit file system changes, especially in directories where core dumps are generated, to detect suspicious symlink creation or file modifications. 4) Employ mandatory access controls (MAC) or filesystem protections to prevent users from creating symlinks in sensitive directories or overwriting critical files. 5) Consider migrating legacy UnixWare systems to more modern, supported platforms to eliminate exposure to unpatched vulnerabilities. 6) Implement robust logging and alerting for local file system activities to quickly identify exploitation attempts.