CVE-2002-0225 in TACACS+
Summary
by MITRE
tac_plus Tacacs+ daemon F4.0.4.alpha, originally maintained by Cisco, creates files from the accounting directive with world-readable and writable permissions, which allows local users to access and modify sensitive files.
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Analysis
by VulDB Data Team • 06/18/2024
The vulnerability identified as CVE-2002-0225 affects the tac_plus daemon version 4.0.4.alpha which was originally developed and maintained by Cisco for implementing the Terminal Access Controller Access-Control System Plus protocol. This daemon serves as a critical component in network access control systems, managing authentication, authorization, and accounting functions for remote access services. The specific flaw manifests in how the daemon handles file creation operations when processing accounting directives, creating a significant security weakness that undermines the integrity and confidentiality of network access logs and related data.
The technical implementation of this vulnerability stems from improper file permission handling within the tac_plus daemon. When the daemon processes accounting directives, it creates log files and data storage components with permissions that allow any local user on the system to read and write to these files. This configuration violates fundamental security principles of least privilege and proper access control enforcement. The daemon fails to implement appropriate file permission controls during the creation phase, resulting in files that are world-readable and world-writable, effectively removing any access restrictions that should normally protect sensitive accounting information.
The operational impact of this vulnerability extends beyond simple data exposure, as it creates opportunities for both information disclosure and data manipulation attacks. Local users who can access these files can potentially read sensitive authentication and authorization data, including user credentials, access patterns, and network activity logs. Furthermore, the writable permissions enable malicious actors to modify or corrupt accounting records, which could lead to unauthorized access to network resources, denial of service conditions, or the creation of false audit trails that obscure legitimate network activity. This vulnerability particularly affects environments where the tac_plus daemon runs with elevated privileges and where multiple users share the same system.
The vulnerability aligns with CWE-732 which describes improper permission assignment for critical resources, and represents a classic example of inadequate access control implementation. From an adversary perspective, this weakness maps to ATT&CK technique T1078 which covers legitimate credentials and T1566 which covers credential access through exploitation of weak permissions. Organizations using this daemon are particularly vulnerable in multi-user environments where the daemon is not properly isolated or where privilege separation is inadequate. The impact is exacerbated in environments where accounting data contains sensitive information about user activities, system access patterns, and network behavior that could be exploited for further attacks.
Mitigation strategies should focus on immediate permission adjustments and long-term architectural improvements. System administrators should immediately verify and correct file permissions on accounting files created by the daemon, ensuring that these files are only accessible to the daemon process and authorized administrative users. The daemon should be configured to create files with restrictive permissions such as 600 or 640, preventing unauthorized access while maintaining necessary functionality. Additionally, organizations should consider implementing privilege separation techniques and ensuring that the daemon runs with minimal necessary privileges. Regular security audits should verify that accounting files maintain appropriate access controls, and system monitoring should be implemented to detect unauthorized access attempts to these sensitive data files.