CVE-2012-3500 in devscripts
Summary
by MITRE
scripts/annotate-output.sh in devscripts before 2.12.2, as used in rpmdevtools before 8.3, allows local users to modify arbitrary files via a symlink attack on the temporary (1) standard output or (2) standard error output file.
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Analysis
by VulDB Data Team • 12/14/2021
The vulnerability identified as CVE-2012-3500 represents a classic race condition and symlink attack scenario that affects the devscripts package version 2.12.1 and earlier, which is also utilized by rpmdevtools versions prior to 8.3. This flaw exists within the scripts/annotate-output.sh utility where the script creates temporary files for standard output and standard error redirection without proper validation of symbolic link references. The issue stems from the insecure handling of temporary file creation processes that do not adequately verify the integrity of file paths before writing data to them.
The technical implementation of this vulnerability occurs when the annotate-output.sh script generates temporary files using predictable naming patterns without sufficient security controls to prevent attackers from establishing symbolic links in the target directory. Attackers can exploit this by creating symbolic links with the same names as the temporary files that the script will later use, thereby redirecting output to arbitrary locations on the filesystem. This type of attack falls under the category of time-of-check to time-of-use race conditions and aligns with CWE-367, which specifically addresses time-of-check to time-of-use race conditions that can lead to privilege escalation and unauthorized file access.
The operational impact of this vulnerability extends beyond simple file modification capabilities, as it can enable local privilege escalation attacks when the script executes with elevated privileges or when the targeted files are owned by privileged users. The attack vector requires local system access but can potentially compromise system integrity by allowing attackers to overwrite critical system files, inject malicious content into log files, or redirect program output to locations where it can be subsequently exploited. This vulnerability particularly affects package management workflows where automated scripts handle output redirection, making it a significant concern for system administrators maintaining package repositories and build environments.
Security mitigations for this vulnerability include upgrading to devscripts version 2.12.2 or later, which implements proper temporary file handling mechanisms that prevent symbolic link attacks. Organizations should also implement strict file permissions and directory access controls to limit the scope of potential exploitation. The fix typically involves using secure temporary file creation methods that either employ atomic operations or validate that created files are not symbolic links before proceeding with data writing operations. Additionally, system administrators should monitor for unauthorized file modifications in critical directories and implement proper logging of temporary file operations to detect potential exploitation attempts. This vulnerability demonstrates the importance of secure coding practices and proper input validation in shell scripts, particularly those that handle file I/O operations in multi-user environments where privilege escalation risks are significant. The ATT&CK framework categorizes this type of vulnerability under privilege escalation techniques, specifically targeting the use of insecure temporary file creation methods to gain unauthorized access to system resources.