CVE-2012-6114 in git-extras
Summary
by MITRE
The git-changelog utility in git-extras 1.7.0 allows local users to overwrite arbitrary files via a symlink attack on (1) /tmp/changelog or (2) /tmp/.git-effort.
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Analysis
by VulDB Data Team • 04/22/2023
The vulnerability identified as CVE-2012-6114 resides within the git-changelog utility component of git-extras version 1.7.0, presenting a significant security risk to local users who execute this utility. This flaw manifests as a symlink attack vulnerability that enables malicious local actors to overwrite arbitrary files on the system. The vulnerability specifically targets two temporary file locations: /tmp/changelog and /tmp/.git-effort, which are utilized by the utility during its operation. The attack exploits the predictable naming of temporary files and the lack of proper validation mechanisms that would prevent symbolic link exploitation.
The technical implementation of this vulnerability follows a classic race condition pattern where the utility creates temporary files without proper security checks. When git-changelog executes, it generates temporary files in the /tmp directory without verifying whether these files already exist as symbolic links. An attacker can create malicious symbolic links with the same names as the expected temporary files before the utility runs, causing the utility to write data to locations controlled by the attacker rather than the intended temporary locations. This behavior directly aligns with CWE-377, which addresses insecure temporary file creation practices, and represents a variant of the broader class of symlink-based attacks that have been documented in numerous security advisories.
The operational impact of this vulnerability extends beyond simple file overwrites, as it provides attackers with the capability to modify critical system files or inject malicious content into the git repository's changelog functionality. The exploitation of this vulnerability can lead to persistent backdoors, data corruption, or unauthorized privilege escalation depending on the context in which the git-changelog utility is executed. Attackers can leverage this weakness to modify version control history, inject malicious code into changelog entries, or potentially compromise the integrity of the entire git repository. This vulnerability particularly affects systems where users have the ability to execute git-changelog or where the utility is used in automated scripts, making it a significant concern for development environments and continuous integration systems.
Mitigation strategies for CVE-2012-6114 should focus on immediate patching of the git-extras package to version 1.7.1 or later, which contains the necessary fixes to address the symlink attack vulnerability. Organizations should implement proper temporary file handling practices by using secure temporary file creation methods that prevent symbolic link attacks, such as creating temporary files with unique names and proper permissions. The fix typically involves implementing checks to ensure that temporary files are created atomically and that symbolic links are not followed when creating temporary files. System administrators should also consider implementing additional security measures including restricting write access to the /tmp directory for non-privileged users and monitoring for suspicious file creation patterns. This vulnerability demonstrates the importance of following secure coding practices and adheres to ATT&CK technique T1548.001, which covers the exploitation of local privilege escalation mechanisms through insecure file handling practices. Organizations should also consider implementing process monitoring to detect and prevent unauthorized file overwrites and maintain updated security baselines that address known vulnerabilities in development tools and utilities.