CVE-2000-0164 is a vulnerability affecting Sun Internet Mail Server (SIMS) version 2.0 running on Solaris ISP Server platforms. The core issue arises during the installation process of SIMS, which creates a file with world-readable permissions. This file contains sensitive information, specifically user passwords, that local users on the system can access. Because the file is world-readable, any local user, regardless of privilege level, can read the file and extract password data, leading to a complete compromise of confidentiality, integrity, and availability of the mail server accounts. The vulnerability does not require authentication or remote access; it is exploitable by any local user with access to the system. The CVSS v2 score of 7.2 reflects a high severity, with the vector indicating local access required (AV:L), low attack complexity (AC:L), no authentication needed (Au:N), and full impact on confidentiality, integrity, and availability (C:C/I:C/A:C). No patch is 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 the affected product. However, the risk remains significant in environments where SIMS 2.0 is still deployed, especially in legacy systems. The vulnerability highlights poor file permission management during installation, a common security oversight in older software. Exploitation could lead to unauthorized access to mail accounts, data leakage, and potential lateral movement within the affected network.

For European organizations still operating Solaris ISP Server with SIMS 2.0, this vulnerability poses a critical risk to internal mail communications. Compromise of mail server credentials can lead to unauthorized access to sensitive corporate communications, intellectual property, and personal data, violating GDPR and other data protection regulations. The integrity of email systems could be undermined, enabling attackers to send spoofed or malicious emails internally or externally, facilitating phishing or social engineering attacks. Availability could also be impacted if attackers disrupt mail services or lock out legitimate users. Given the local access requirement, the threat is primarily from insider threats or attackers who have already gained limited access to the network. However, the ease of exploitation once local access is obtained makes it a significant risk in multi-user environments or where physical or remote local access is possible. The lack of a patch means organizations must rely on compensating controls. The impact is exacerbated in sectors with high regulatory scrutiny such as finance, healthcare, and government institutions prevalent across Europe.

1. Immediately audit all Solaris ISP Server systems to identify installations of SIMS version 2.0. 2. Restrict local user access to affected systems strictly, limiting the number of users with shell or console access. 3. Manually inspect and modify file permissions of the world-readable file created during SIMS installation to restrict access to only the mail server service account or root. Use chmod 600 or more restrictive permissions as appropriate. 4. Implement host-based intrusion detection systems (HIDS) to monitor unauthorized access attempts to sensitive files. 5. Where possible, migrate mail services from SIMS 2.0 to modern, supported mail server solutions with active security maintenance. 6. Employ strict network segmentation to isolate legacy Solaris servers from general user networks, minimizing local access opportunities. 7. Enforce strong physical security controls to prevent unauthorized physical access to servers. 8. Regularly review and update user account privileges and remove unnecessary accounts on Solaris systems. 9. Conduct security awareness training for system administrators on legacy system risks and secure configuration practices. 10. If migration is not immediately feasible, consider deploying file integrity monitoring tools to alert on permission changes or access to sensitive files.