CVE-1999-0975 is a vulnerability in the Windows 95 help system that allows a local attacker to execute arbitrary commands with the privileges of another user. The issue arises from the way the Windows help system processes table of contents metafiles (.CNT files). By editing the .CNT file and modifying the topic action, an attacker can embed commands that will be executed when the associated .hlp help file is accessed. This vulnerability exploits the trust relationship between the help system and the .CNT file format, enabling command execution without requiring elevated privileges initially. The attack vector is local, meaning the attacker must have access to the system to modify or create malicious .CNT files. The vulnerability impacts confidentiality, integrity, and availability since arbitrary commands can be run, potentially leading to privilege escalation, data manipulation, or system disruption. The CVSS score of 4.6 (medium severity) reflects the local attack vector and the lack of required authentication, but the potential for partial compromise of the system. No patch is available, and there are no known exploits in the wild, likely due to the age of the affected system (Windows 95) and the limited scope of affected versions.

For European organizations, the direct impact of CVE-1999-0975 is minimal today because it affects Windows 95, an obsolete operating system no longer in use in enterprise environments. However, if legacy systems running Windows 95 are still in operation within certain industrial or embedded environments, this vulnerability could allow local attackers to execute arbitrary commands, potentially leading to unauthorized access or disruption of critical systems. The vulnerability could be exploited to compromise data confidentiality, alter system configurations, or disrupt availability. Given the local access requirement, the threat is more relevant in environments where physical or local network access is possible, such as manufacturing plants or legacy IT infrastructure. The lack of available patches means organizations relying on affected systems must consider compensating controls or system upgrades to mitigate risk.

Since no official patch exists for this vulnerability, European organizations should prioritize the following mitigations: 1) Identify and inventory any legacy systems still running Windows 95 or affected versions; 2) Isolate legacy systems from general network access, especially restricting local user access and removable media usage; 3) Implement strict access controls and monitoring on systems where local access is possible to detect unauthorized file modifications; 4) Where feasible, upgrade or replace legacy systems with supported operating systems that receive security updates; 5) Educate users about the risks of opening or modifying help files and .CNT files from untrusted sources; 6) Employ application whitelisting or endpoint protection solutions that can detect or block unauthorized execution of commands triggered by help files.