CVE-2000-0118 is a vulnerability in the Red Hat Linux 'su' program, which is used to switch user identities, typically to gain root privileges. The flaw exists because the 'su' program fails to log failed password attempts if the 'su' process is terminated prematurely before it times out. This logging omission allows local attackers to perform brute force password guessing attacks without leaving audit trails of their failed attempts. Since the 'su' command is a critical component for privilege escalation on Linux systems, this vulnerability undermines the system's ability to detect and respond to unauthorized access attempts. The vulnerability affects multiple versions of Red Hat Linux spanning from early releases (1.1.3) through versions 6.1 and various sub-versions, indicating a broad impact across many legacy systems. The CVSS score of 7.2 (high severity) reflects the significant confidentiality, integrity, and availability impact possible if exploited. The attack vector is local, requiring the attacker to have some level of access to the system, but no authentication is needed to attempt password guesses. Exploitation does not require user interaction beyond the attacker’s own actions. Although no patches are currently available and no known exploits are reported in the wild, the vulnerability remains a concern for legacy systems still in operation. The lack of logging impairs forensic analysis and intrusion detection, increasing the risk of undetected privilege escalation attacks.

For European organizations, especially those running legacy Red Hat Linux systems in critical infrastructure, government, or enterprise environments, this vulnerability poses a risk of undetected privilege escalation. Attackers with local access could brute force root passwords without triggering security alerts, potentially leading to full system compromise. This could result in unauthorized data access, modification, or destruction, impacting confidentiality and integrity. Availability could also be affected if attackers disrupt system operations after gaining root access. The inability to log failed attempts hinders incident response and forensic investigations, increasing dwell time for attackers. Organizations relying on legacy Red Hat Linux versions in sectors such as finance, healthcare, manufacturing, or public administration may face compliance and operational risks if this vulnerability is exploited.

Since no official patch is available, European organizations should prioritize upgrading affected Red Hat Linux systems to supported, patched versions where this vulnerability is resolved. If upgrading is not immediately feasible, organizations should implement compensating controls such as: 1) Restricting local access to trusted users only, minimizing the attack surface. 2) Employing enhanced monitoring tools that detect abnormal 'su' process terminations or unusual authentication patterns, even if failed attempts are not logged by 'su' itself. 3) Using alternative privilege escalation methods or tools that provide robust logging and auditing capabilities. 4) Implementing strict physical and network access controls to prevent unauthorized local access. 5) Conducting regular security audits and penetration tests focused on privilege escalation vectors. 6) Deploying host-based intrusion detection systems (HIDS) that can monitor process behavior and alert on suspicious activities related to 'su' usage. These measures help mitigate risk until systems can be fully updated.