CVE-2009-0032 in CUPS
Summary
by MITRE
CUPS on Mandriva Linux 2008.0, 2008.1, 2009.0, Corporate Server (CS) 3.0 and 4.0, and Multi Network Firewall (MNF) 2.0 allows local users to overwrite arbitrary files via a symlink attack on the /tmp/pdf.log temporary file.
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Analysis
by VulDB Data Team • 05/23/2025
The vulnerability described in CVE-2009-0032 represents a critical file system security flaw affecting the Common Unix Printing System (CUPS) implementation on various Mandriva Linux distributions. This issue stems from improper handling of temporary files during the printing process, specifically concerning the /tmp/pdf.log file that CUPS creates during PDF generation operations. The vulnerability manifests when local attackers exploit a race condition or symbolic link manipulation technique to redirect file operations to arbitrary locations on the system.
The technical root cause of this vulnerability lies in the insecure temporary file creation pattern used by CUPS, which creates temporary files with predictable names in the /tmp directory without proper security checks. When CUPS processes print jobs that generate PDF output, it creates a pdf.log file in the /tmp directory to store logging information. However, the implementation fails to verify whether the target temporary file already exists or to use secure methods for creating temporary files, such as creating files with unique names or using proper file permissions. This insecure practice allows local users to establish symbolic links in the /tmp directory that point to sensitive system files or locations where they wish to overwrite content.
The operational impact of this vulnerability extends beyond simple file overwriting, as it provides local attackers with a mechanism to potentially compromise system integrity and confidentiality. An attacker with local access can leverage this vulnerability to overwrite critical system files, configuration files, or even log files that might contain sensitive information. This could lead to privilege escalation opportunities, denial of service conditions, or the ability to inject malicious content into system processes that rely on the overwritten files. The vulnerability is particularly concerning because it does not require network access or special privileges beyond local system access, making it exploitable in scenarios where attackers have already gained a foothold on the system through other means.
From a cybersecurity perspective, this vulnerability aligns with CWE-377: Insecure Temporary File creation and CWE-378: Creation of Temporary File With Insecure Permissions, both of which are fundamental security weaknesses that have been consistently identified as critical risks in software development practices. The attack pattern used in this vulnerability corresponds to the ATT&CK technique T1059.007: Command and Scripting Interpreter: PowerShell, though more accurately it represents a classic symlink attack pattern that has been documented in various exploit frameworks. The vulnerability demonstrates how seemingly minor implementation details in file handling can create significant security risks, particularly in systems that handle sensitive operations like printing and document processing.
Mitigation strategies for this vulnerability should focus on immediate patching of affected CUPS implementations and implementation of secure temporary file handling practices. Organizations should ensure that all affected Mandriva Linux systems are updated to versions that properly address this vulnerability through secure temporary file creation mechanisms. Additionally, system administrators should implement proper file system permissions and access controls, particularly for the /tmp directory, and consider implementing monitoring for suspicious symbolic link creation activities. The vulnerability also highlights the importance of following secure coding practices and conducting thorough security testing of temporary file operations, particularly in multi-user environments where local privilege escalation risks are elevated. Regular security audits and vulnerability assessments should include verification of temporary file handling practices to prevent similar issues from arising in other system components or custom applications.