CVE-2014-5031 in CUPS
Summary
by MITRE
The web interface in CUPS before 2.0 does not check that files have world-readable permissions, which allows remote attackers to obtains sensitive information via unspecified vectors.
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Analysis
by VulDB Data Team • 02/09/2022
The vulnerability identified as CVE-2014-5031 affects the Common Unix Printing System (CUPS) version 1.x and earlier, specifically targeting the web interface component that handles print job management and system configuration. This flaw represents a critical security oversight in the way CUPS manages file access controls within its web-based administrative interface. The issue stems from inadequate permission validation mechanisms that fail to properly enforce file system access restrictions, creating potential exposure pathways for unauthorized information disclosure. The vulnerability exists in the pre-2.0 versions of CUPS, indicating a long-standing weakness that affected numerous deployments across various Unix-like operating systems including Linux distributions and BSD variants. The web interface serves as a primary management entry point for administrators to configure print services, monitor jobs, and manage printer settings, making it a prime target for attackers seeking to escalate privileges or extract sensitive system information.
The technical root cause of this vulnerability lies in the improper implementation of file permission checks within the CUPS web interface component. When CUPS processes file operations through its web administration interface, it fails to validate whether the files being accessed have world-readable permissions that would allow unauthorized users to view their contents. This flaw specifically affects how the system handles file access control lists and permission verification during web-based operations, essentially bypassing the standard security checks that should prevent unauthorized access to sensitive files. The vulnerability manifests when remote attackers can leverage the web interface to access files that should normally be restricted, potentially exposing system configuration details, user credentials, or other sensitive information stored in accessible file locations. This represents a classic case of insufficient access control implementation where the system assumes that web interface users have appropriate authorization levels without proper validation of file system permissions.
The operational impact of CVE-2014-5031 extends beyond simple information disclosure, as it creates opportunities for attackers to gather intelligence that could lead to more sophisticated attacks. An attacker who successfully exploits this vulnerability could potentially access printer configuration files, system logs, user account information, or other sensitive data that might reveal network topology, authentication methods, or system vulnerabilities. The attack vector is particularly concerning because it leverages the web interface, which is often accessible from external networks for remote administration purposes, making the vulnerability exploitable from outside the local network boundary. This weakness could enable attackers to perform reconnaissance activities, gather system information for further exploitation, or potentially escalate privileges by accessing files that contain authentication tokens or other sensitive data. The impact is particularly severe in environments where CUPS is used to manage enterprise printing infrastructure, as these systems often contain sensitive corporate information and serve as critical components of networked computing environments.
The vulnerability aligns with CWE-732: Incorrect Permission Assignment for Critical Resource, which specifically addresses cases where security-critical resources are assigned incorrect permissions that allow unauthorized access. From an ATT&CK framework perspective, this vulnerability maps to T1083: File and Directory Discovery, as attackers can use the flaw to enumerate and access files that should be protected. The flaw also relates to T1566: Phishing with Social Engineering, as the web interface is often designed to be accessible to users who might not have proper authorization levels, creating potential social engineering opportunities. Organizations using affected CUPS versions face significant risk of unauthorized information disclosure, particularly in environments where the web interface is exposed to untrusted networks or where administrative access is not properly secured. The vulnerability demonstrates a fundamental failure in implementing proper access control mechanisms within the web interface, which should have included mandatory permission checks before allowing file access operations to proceed.
The recommended mitigations for CVE-2014-5031 include immediate upgrading to CUPS version 2.0 or later, which includes proper permission checking mechanisms for web interface file operations. Organizations should also implement network segmentation to restrict access to the CUPS web interface to trusted administrative networks only, and disable the web interface if it is not required for operations. Additional measures include configuring proper file system permissions for CUPS-related files, implementing network access controls using firewalls, and regularly auditing access logs for suspicious activities. Security administrators should also consider disabling unnecessary web interface features and ensuring that only authorized personnel have access to the administrative functions. The vulnerability highlights the importance of proper input validation and access control implementation in web-based administrative interfaces, emphasizing that all file operations should be subject to proper permission verification before execution. Organizations should also implement regular security assessments to identify similar permission-related vulnerabilities in other system components and ensure that all administrative interfaces follow secure coding practices that prevent unauthorized access to sensitive resources.