CVE-2012-4510 in cups-pk-helper
Summary
by MITRE
cups-pk-helper before 0.2.3 does not properly wrap the (1) cupsGetFile and (2) cupsPutFile function calls, which allows user-assisted remote attackers to read or overwrite sensitive files using CUPS resources.
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Analysis
by VulDB Data Team • 12/20/2021
The vulnerability identified as CVE-2012-4510 affects cups-pk-helper version 0.2.3 and earlier, representing a critical security flaw in the Common Unix Printing System helper application. This issue stems from improper handling of CUPS function calls, specifically the cupsGetFile and cupsPutFile operations, which are fundamental components for managing printer configuration and document processing within Unix-like operating systems. The vulnerability exists within the privilege escalation mechanism that cups-pk-helper employs to interact with CUPS resources on behalf of users, creating a pathway for malicious actors to exploit the system's printing infrastructure.
The technical flaw manifests through the inadequate sanitization and validation of file paths and resource identifiers when these CUPS functions are invoked. When cups-pk-helper processes print jobs or configuration requests, it relies on the cupsGetFile and cupsPutFile functions to access system files and resources. However, the helper application fails to properly validate or sanitize input parameters, allowing attackers to manipulate these function calls to target arbitrary files on the system. This improper wrapping creates a directory traversal vulnerability where attackers can specify file paths that bypass normal access controls, potentially enabling them to read sensitive system files or overwrite critical configuration data.
The operational impact of this vulnerability extends beyond simple file access, as it provides attackers with the capability to manipulate the printing system's core functionality and potentially escalate privileges within the system. Attackers can leverage this vulnerability to read system configuration files, access printer driver information, or even modify critical system resources that control print queue operations. The user-assisted nature of this attack means that an attacker needs to convince a legitimate user to perform an action that triggers the vulnerable code path, such as submitting a malicious print job or configuring a printer with crafted parameters. This approach aligns with attack patterns described in the ATT&CK framework under privilege escalation techniques, particularly those involving system service manipulation and credential access through legitimate system tools.
The vulnerability's classification under CWE-22, "Improper Limitation of a Pathname to a Restricted Directory," highlights the core issue of insufficient input validation and path manipulation. This weakness allows attackers to traverse file system paths beyond intended boundaries, potentially accessing sensitive files such as configuration data, authentication tokens, or system binaries. The impact is particularly severe in environments where cups-pk-helper runs with elevated privileges, as it provides a direct pathway for attackers to compromise the entire printing infrastructure and potentially gain deeper system access. Organizations running affected versions of cups-pk-helper should prioritize immediate patching to address this vulnerability, as the combination of user-assisted exploitation and the privileged execution context creates a significant risk to system integrity and confidentiality.
Mitigation strategies should include immediate deployment of cups-pk-helper version 0.2.3 or later, which implements proper input validation and path sanitization for CUPS function calls. System administrators should also consider implementing additional security controls such as restricting access to the cups-pk-helper service, monitoring print job submissions for suspicious activity, and applying principle of least privilege configurations to minimize the impact if exploitation occurs. The vulnerability demonstrates the importance of proper input validation in privilege escalation tools and highlights the need for comprehensive security testing of system helper applications that interface with critical system resources. Organizations should also review their printing system configurations and implement network segmentation to limit potential attack vectors, as this vulnerability can be exploited remotely through network-based printing services.