CVE-2005-3343 in tkdiff
Summary
by MITRE
tkdiff before 4.1.1 allows local users to overwrite arbitrary files via a symlink attack on temporary files.
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Analysis
by VulDB Data Team • 07/10/2019
The vulnerability identified as CVE-2005-3343 affects tkdiff versions prior to 4.1.1 and represents a classic file system race condition that enables local privilege escalation through symbolic link manipulation. This issue arises from the application's improper handling of temporary files during its operation, creating a window of opportunity for malicious users to exploit the system's file creation processes. The vulnerability specifically targets the temporary file creation mechanism where tkdiff generates temporary files without adequate security measures to prevent symbolic link attacks.
The technical flaw manifests when tkdiff creates temporary files in a predictable location without verifying whether the target path already exists as a symbolic link. Attackers can exploit this by creating a symbolic link with the same name as the temporary file that tkdiff intends to create, pointing it to a sensitive system file such as /etc/passwd or another critical location. When tkdiff executes and attempts to create its temporary file, the system creates the symbolic link target instead of the intended temporary file, effectively allowing the attacker to overwrite arbitrary files with arbitrary content. This type of vulnerability falls under the CWE-377 weakness category, specifically CWE-377: Insecure Temporary File, which is classified as a high-severity issue due to its potential for privilege escalation and system compromise.
The operational impact of this vulnerability extends beyond simple file overwriting capabilities as it provides attackers with the means to modify critical system files, potentially leading to complete system compromise. Local users who can execute tkdiff can leverage this vulnerability to modify system configuration files, replace binaries with malicious versions, or manipulate authentication files to gain elevated privileges. The vulnerability is particularly dangerous in multi-user environments where less privileged users might exploit it to escalate their privileges or disrupt system operations. From an attack framework perspective, this vulnerability aligns with the ATT&CK technique T1059.001 for command and scripting interpreter and T1068 for exploit for privilege escalation, demonstrating how local file system vulnerabilities can be weaponized for broader system compromise.
Mitigation strategies for CVE-2005-3343 involve implementing proper temporary file handling procedures that ensure file creation security. System administrators should immediately upgrade to tkdiff version 4.1.1 or later where this vulnerability has been patched. The patch typically addresses the issue by using secure temporary file creation methods such as creating temporary files with unique names and proper permissions, or by employing the O_CREAT and O_EXCL flags during file creation to prevent race conditions. Organizations should also implement the principle of least privilege, limiting the execution of tkdiff to only necessary users and processes. Additional protective measures include monitoring for suspicious temporary file creation patterns and implementing file system integrity monitoring to detect unauthorized file modifications. The vulnerability serves as a reminder of the critical importance of secure coding practices in file system operations and the necessity of following security guidelines such as those outlined in the Open Web Application Security Project (OWASP) secure coding practices for preventing temporary file vulnerabilities.