CVE-2005-3124 in thttpd
Summary
by MITRE
syslogtocern in Acme thttpd before 2.23 allows local users to write arbitrary files via a symlink attack on a temporary file.
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Analysis
by VulDB Data Team • 08/04/2019
The vulnerability identified as CVE-2005-3124 affects the syslogtocern utility within the Acme thttpd web server version 2.23 and earlier. This represents a critical security flaw that stems from improper handling of temporary files during the execution of the syslogtocern utility, which is designed to convert syslog messages into CERN-style log files for web server monitoring purposes. The vulnerability specifically manifests when the utility creates temporary files without adequate security measures to prevent symbolic link attacks, creating a pathway for local attackers to manipulate the file system.
The technical implementation of this vulnerability resides in the insufficient validation of temporary file creation processes within the syslogtocern utility. When the utility executes, it generates temporary files in predictable locations without proper checks to ensure these files are not symbolic links pointing to arbitrary system locations. This flaw allows an attacker with local access to create malicious symbolic links in the temporary file directory before the utility processes them, causing the utility to write data to unintended targets. The vulnerability aligns with CWE-377, which addresses insecure temporary file creation practices, and specifically demonstrates weaknesses in file system permissions and race condition exploitation.
The operational impact of this vulnerability extends beyond simple file system manipulation, as it provides attackers with the ability to overwrite critical system files, inject malicious content into log files, or potentially escalate privileges depending on the execution context of the syslogtocern utility. Since the utility typically runs with elevated privileges during log processing operations, successful exploitation could lead to unauthorized system modifications or data corruption. The attack vector requires local system access but does not need network connectivity, making it particularly dangerous in environments where local privilege escalation is a concern. This vulnerability directly maps to ATT&CK technique T1059.007 for command and script injection, as attackers could leverage this to modify system files through the logging mechanism.
Mitigation strategies for CVE-2005-3124 should focus on immediate patching of the thttpd web server to version 2.23 or later, where the vulnerability has been addressed through proper temporary file handling. System administrators should also implement additional security controls such as restricting write permissions on temporary directories, monitoring for suspicious symbolic link creation patterns, and ensuring that the syslogtocern utility runs with minimal necessary privileges. The fix typically involves implementing proper file descriptor validation and using secure temporary file creation methods that prevent symbolic link attacks. Organizations should also consider implementing file integrity monitoring solutions to detect unauthorized modifications to critical system files and log structures that could result from this vulnerability.