CVE-2005-1916 in ekg
Summary
by MITRE
linki.py in ekg 2005-06-05 and earlier allows local users to overwrite or create arbitrary files via a symlink attack on temporary files.
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Analysis
by VulDB Data Team • 06/07/2019
The vulnerability identified as CVE-2005-1916 resides within the linki.py script component of the ekg software version 2005-06-05 and earlier. This represents a classic symlink attack scenario that exploits improper handling of temporary files during script execution. The flaw manifests when the script creates temporary files without adequate security measures to prevent symbolic link manipulation by local users. The vulnerability falls under the category of insecure temporary file creation as classified by CWE-377, specifically involving the creation of temporary files with predictable names in world-writable directories.
The technical implementation of this vulnerability stems from the script's failure to validate or properly secure temporary file creation processes. When linki.py executes, it generates temporary files that are susceptible to symbolic link attacks, allowing malicious local users to create or overwrite arbitrary files on the system. The attack vector relies on the attacker creating a symbolic link with the same name as a temporary file that the vulnerable script will create, thereby redirecting file operations to locations controlled by the attacker. This technique aligns with the ATT&CK framework's T1548.001 tactic for privilege escalation through the manipulation of file permissions and symbolic links.
The operational impact of this vulnerability extends beyond simple file manipulation as it provides attackers with potential pathways for privilege escalation and persistent system compromise. Local users who can execute the vulnerable script gain the ability to overwrite critical system files, modify configuration data, or inject malicious content into the system. The vulnerability is particularly concerning because it requires no special privileges beyond local access, making it an attractive target for attackers seeking to establish footholds within systems. The attack can be executed through simple commands that create symbolic links in the temporary directory, followed by triggering the vulnerable script execution.
Mitigation strategies for this vulnerability should focus on implementing proper temporary file handling practices that prevent symbolic link attacks. The recommended approach involves using secure temporary file creation functions that ensure file uniqueness and proper permissions, such as the mkstemp family of functions in Unix-like systems. Additionally, the script should avoid creating temporary files in world-writable directories and should implement proper validation of temporary file paths before operations occur. Organizations should also consider implementing mandatory access controls and file system permissions that restrict symbolic link creation in sensitive directories. The vulnerability serves as a prime example of why the principle of least privilege and secure coding practices are essential in preventing local privilege escalation attacks. System administrators should also implement monitoring for suspicious file creation patterns and ensure that all software components undergo regular security assessments to identify similar vulnerabilities in the codebase.