CVE-2005-0159 in Linux
Summary
by MITRE
The tpkg-* scripts in the toolchain-source 3.0.4 package on Debian GNU/Linux 3.0 allow local users to overwrite arbitrary files via a symlink attack on temporary files.
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Analysis
by VulDB Data Team • 04/22/2019
The vulnerability described in CVE-2005-0159 represents a classic file system race condition and privilege escalation issue affecting the toolchain-source package version 3.0.4 on Debian GNU/Linux 3.0 systems. This flaw specifically targets the tpkg-* scripts which are part of the build toolchain used for creating software packages. The vulnerability stems from improper handling of temporary files during script execution, creating a window where malicious users can manipulate the system by exploiting symbolic link attacks against these temporary resources.
The technical implementation of this vulnerability involves a time-of-check to time-of-use (TOCTOU) race condition where the scripts perform operations on temporary files that can be manipulated by attackers through symlink creation. When the tpkg-* scripts execute, they create temporary files in predictable locations and subsequently reference these files in their operations. Local users can exploit this by creating symbolic links in the expected temporary file locations before the scripts execute, causing the scripts to write data to attacker-controlled locations rather than intended targets. This type of vulnerability is classified under CWE-367 which specifically addresses time-of-check to time-of-use race conditions that can lead to privilege escalation and arbitrary file overwrites.
The operational impact of this vulnerability extends beyond simple file manipulation as it can enable local users to escalate privileges and potentially compromise the entire system. An attacker with local access can leverage this vulnerability to overwrite critical system files, modify configuration data, or even inject malicious code into the build process. The attack vector is particularly dangerous because it requires minimal privileges and can be executed by any user with access to the system, making it a significant concern for multi-user environments where system integrity is paramount. This vulnerability directly aligns with ATT&CK technique T1068 which covers local privilege escalation through race conditions and file system manipulation.
Mitigation strategies for this vulnerability should focus on immediate patching of the affected toolchain-source package to version 3.0.5 or later, which contains the necessary fixes to prevent the symbolic link attack vectors. System administrators should also implement proper temporary file handling practices by using secure temporary file creation methods that prevent symlink attacks, such as creating temporary files with unique names and proper permissions. Additionally, privilege separation mechanisms should be enforced to limit the impact of such vulnerabilities, ensuring that scripts run with minimal necessary privileges. The broader security posture should include regular vulnerability assessments and monitoring for similar race condition vulnerabilities in other system components, particularly those involving temporary file creation and manipulation. Organizations should also consider implementing automated patch management systems to ensure timely remediation of such critical vulnerabilities.