CVE-2004-1377 in Turbolinux Server
Summary
by MITRE
The (1) fixps (aka fixps.in) and (2) psmandup (aka psmandup.in) scripts in a2ps before 4.13 allow local users to overwrite arbitrary files via a symlink attack on temporary files.
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Analysis
by VulDB Data Team • 06/05/2019
The vulnerability identified as CVE-2004-1377 affects the a2ps package version 4.13 and earlier, specifically targeting two critical scripts named fixps.in and psmandup.in. This issue represents a classic symlink attack vulnerability that exploits the insecure handling of temporary files within these utility scripts. The flaw allows local attackers to manipulate the file system by creating symbolic links that point to sensitive system files, enabling them to overwrite or modify content in locations they would normally not have access to. The vulnerability stems from the scripts' failure to properly validate or secure temporary file creation processes, creating a window of opportunity for privilege escalation and data corruption.
The technical exploitation of this vulnerability involves the attacker creating symbolic links with specific names in directories where the a2ps scripts expect to find temporary files. When the scripts execute and attempt to write to these expected temporary locations, they inadvertently write to the attacker-controlled symbolic link targets instead of the intended temporary files. This behavior aligns with CWE-377, which addresses insecure temporary file creation practices, and demonstrates how improper file handling can lead to privilege escalation and unauthorized file manipulation. The attack vector specifically targets the race condition between temporary file creation and access, where the attacker can establish a symlink before or during the script's temporary file operations.
The operational impact of this vulnerability extends beyond simple file overwrites, potentially enabling attackers to modify critical system files, inject malicious code into the print processing pipeline, or compromise the integrity of the entire a2ps utility framework. Local users who can execute these scripts gain the ability to escalate privileges and manipulate system resources, making this a significant concern for multi-user systems where different users may have varying levels of access. The vulnerability affects systems where a2ps is installed and executed with elevated privileges, particularly in environments where print management services are actively used. This weakness can be leveraged as part of broader attack chains, potentially leading to persistent backdoors or complete system compromise through the manipulation of print-related processes.
Security mitigations for CVE-2004-1377 require immediate patching of the a2ps package to version 4.13 or later, where the problematic temporary file handling has been corrected. System administrators should also implement proper file permissions and ownership controls for the affected scripts, ensuring that temporary file creation uses secure methods such as creating files with unique names and proper permissions before any symbolic link manipulation can occur. The remediation process should include verifying that no symbolic links exist in directories where temporary files are created, and implementing monitoring for suspicious file creation patterns. From an ATT&CK framework perspective, this vulnerability maps to privilege escalation techniques and can be categorized under T1068, which addresses local privilege escalation through insecure file handling, making it a critical target for both defensive and offensive security operations.