CVE-2014-5029 in CUPS
Summary
by MITRE
The web interface in CUPS 1.7.4 allows local users in the lp group to read arbitrary files via a symlink attack on a file in /var/cache/cups/rss/ and language[0] set to null. NOTE: this vulnerability exists because of an incomplete fix for CVE-2014-3537.
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Analysis
by VulDB Data Team • 02/09/2022
The vulnerability described in CVE-2014-5029 represents a critical privilege escalation and information disclosure flaw within the Common Unix Printing System CUPS 1.7.4 web interface. This vulnerability specifically affects systems where local users belong to the lp group, which typically represents printer administrators and users with printing privileges. The flaw arises from inadequate file access controls and improper handling of symbolic link operations within the CUPS web interface, creating a pathway for unauthorized file access that bypasses normal security boundaries.
The technical implementation of this vulnerability exploits the incomplete remediation of a previous vulnerability CVE-2014-3537, indicating a pattern of security regressions in the CUPS software. The attack vector specifically targets the /var/cache/cups/rss/ directory, which serves as a cache location for RSS feed data related to printer status and information. When a malicious user manipulates the language parameter to a null value, the system fails to properly validate symbolic link references during file processing operations. This allows attackers to create or manipulate symbolic links that point to arbitrary files on the system, effectively enabling them to read files that should normally be restricted to authorized users only.
The operational impact of this vulnerability extends beyond simple information disclosure, as it provides local attackers with the ability to access sensitive system files that may contain credentials, configuration data, or other confidential information. The vulnerability is particularly concerning because it requires minimal privileges to exploit, as users only need membership in the lp group, which is commonly granted to users who need to manage printing operations. This makes the attack surface significantly larger than vulnerabilities requiring root access or more specialized privileges, potentially affecting numerous enterprise environments where printer management is widely distributed.
From a cybersecurity framework perspective, this vulnerability maps directly to CWE-59, which describes improper link resolution without limit checks, and aligns with ATT&CK technique T1059 for command and script interpretation. The vulnerability demonstrates poor input validation and inadequate access control mechanisms, both of which are fundamental security principles that should be enforced at multiple layers of system architecture. Organizations should consider implementing additional monitoring of the /var/cache/cups/rss/ directory and related printing system components, as well as ensuring that all updates and patches are properly applied to prevent regression vulnerabilities.
The remediation strategy for CVE-2014-5029 requires immediate patching of the CUPS software to address the incomplete fix for CVE-2014-3537. System administrators should also implement proper file access controls and symbolic link validation within the affected directories, particularly ensuring that no user with lp group membership can manipulate the symbolic link resolution process. Additionally, organizations should conduct comprehensive audits of their printing system configurations and consider implementing more restrictive file permissions for cache directories. The vulnerability serves as a reminder of the importance of thorough testing when implementing security patches and the necessity of maintaining proper version control and change management processes for critical system components.