CVE-2004-0404 in Logcheck
Summary
by MITRE
logcheck before 1.1.1 allows local users to overwrite arbitrary files via a symlink attack on a temporary directory in /var/tmp.
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Analysis
by VulDB Data Team • 04/29/2019
The vulnerability described in CVE-2004-0404 represents a classic file system race condition that affects the logcheck utility version 1.1.0 and earlier. This issue arises from improper handling of temporary files during the execution of logcheck scripts, creating an exploitable scenario where local attackers can manipulate the system's file permissions and overwrite arbitrary files through symbolic link manipulation. The vulnerability specifically targets the temporary directory located at /var/tmp, which serves as a staging area for temporary files during logcheck operations. This weakness is particularly concerning because it allows attackers with minimal privileges to potentially escalate their access or disrupt system operations by replacing critical system files with malicious counterparts.
The technical flaw stems from the logcheck utility's failure to properly validate or secure temporary file creation processes. When logcheck executes, it creates temporary files in /var/tmp without implementing proper security measures such as creating files with exclusive access permissions or using secure temporary file creation functions. Attackers can exploit this by creating symbolic links in the /var/tmp directory that point to sensitive system files before logcheck attempts to create its temporary files. This race condition occurs between the time when the application checks for file existence and when it actually creates the file, providing attackers with a window to establish malicious symlinks that will be followed by the vulnerable application. The vulnerability aligns with CWE-377, which addresses insecure temporary file creation practices, and CWE-378, which covers the creation of temporary files with insecure permissions.
The operational impact of this vulnerability extends beyond simple file overwriting, as it can potentially lead to privilege escalation or system compromise when attackers target critical system files such as configuration files, binary executables, or system logs. Local users who can write to /var/tmp can leverage this vulnerability to replace important system files with malicious versions, potentially allowing them to execute arbitrary code with elevated privileges. The attack vector is particularly dangerous because it requires minimal privileges and can be executed by any local user who has write access to the temporary directory. This vulnerability also affects the integrity of system logging mechanisms, as attackers can manipulate logcheck's output files to hide their activities or redirect log data to malicious locations. According to ATT&CK framework, this vulnerability maps to T1059 for command and script injection and T1548.001 for abuse of system permissions, demonstrating how local privilege escalation can occur through insecure temporary file handling.
Mitigation strategies for this vulnerability involve implementing proper temporary file creation practices that prevent symbolic link attacks. System administrators should upgrade to logcheck version 1.1.1 or later, which contains fixes for this specific issue. The recommended approach includes using secure temporary file creation methods that employ exclusive access permissions and avoid predictable temporary file names. Organizations should also implement proper file system permissions and access controls on temporary directories, ensuring that only authorized processes can create or modify files within these locations. Additional protective measures include monitoring for unauthorized symbolic link creation in temporary directories and implementing file integrity monitoring solutions to detect unauthorized file modifications. The fix typically involves modifying the application to use functions such as mkstemp() instead of mktemp() for temporary file creation, which ensures that files are created with exclusive access permissions and prevents attackers from creating symbolic links that would be followed by the application. Regular security audits and vulnerability assessments should be conducted to identify similar insecure temporary file handling practices in other system utilities and applications.