CVE-1999-0476 is a vulnerability identified in SCO TermVision, a component of the SCO OpenServer operating system. The core issue lies in the use of a weak encryption algorithm for password protection. This weak encryption allows local users to easily decrypt stored passwords, compromising their confidentiality. The vulnerability is classified with a CVSS score of 7.2, indicating a high severity level. The attack vector is local (AV:L), meaning an attacker must have local access to the system to exploit the vulnerability. The attack complexity is low (AC:L), and no authentication is required (Au:N) to perform the decryption once local access is obtained. The impact on confidentiality, integrity, and availability is complete (C:C/I:C/A:C), as attackers can obtain plaintext passwords, potentially modify system configurations, and disrupt services. Since the encryption is weak, password hashes or encrypted passwords can be reversed or decrypted with minimal effort, enabling privilege escalation or lateral movement within the affected system. Notably, there is no patch available for this vulnerability, and no known exploits have been reported in the wild. Given the age of the vulnerability (published in 1999), it primarily affects legacy systems still running SCO OpenServer with TermVision, which may be found in some industrial or legacy IT environments.

For European organizations, the impact of this vulnerability depends largely on the presence of SCO OpenServer systems running TermVision. While SCO OpenServer is largely obsolete, some legacy industrial control systems, telecommunications infrastructure, or specialized environments in Europe might still rely on it. If exploited, an attacker with local access could decrypt passwords, leading to unauthorized access, privilege escalation, and potential disruption of critical services. This could compromise sensitive data confidentiality and system integrity, and potentially cause availability issues if attackers modify or disable services. The risk is heightened in environments where physical or local access controls are weak, or where legacy systems are integrated into broader networks without adequate segmentation. Given the high CVSS score and the complete impact on CIA triad, organizations relying on these legacy systems must consider the threat seriously despite the lack of known active exploits.

Since no official patch is available, European organizations should focus on compensating controls. First, restrict local access to systems running SCO OpenServer and TermVision to trusted personnel only, enforcing strict physical and logical access controls. Implement network segmentation to isolate legacy systems from critical network segments and limit exposure. Consider replacing or upgrading legacy SCO OpenServer systems to modern, supported platforms that do not suffer from this vulnerability. If replacement is not immediately feasible, deploy host-based intrusion detection systems (HIDS) to monitor for suspicious activities indicative of password extraction attempts. Regularly audit and review user accounts and passwords on these systems, enforcing strong password policies and changing passwords frequently. Additionally, employ multi-factor authentication where possible to reduce the risk posed by compromised passwords. Finally, maintain comprehensive logging and monitoring to detect unauthorized access attempts promptly.