CVE-2012-1174 in systemd
Summary
by MITRE
The rm_rf_children function in util.c in the systemd-logind login manager in systemd before 44, when logging out, allows local users to delete arbitrary files via a symlink attack on unspecified files, related to "particular records related with user session."
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Analysis
by VulDB Data Team • 12/06/2021
The vulnerability identified as CVE-2012-1174 resides within the systemd-logind login manager component of the systemd suite, specifically within the rm_rf_children function located in util.c. This flaw represents a classic symlink attack scenario that exploits the insecure handling of temporary files during user session termination processes. The vulnerability affects systemd versions prior to 44 and enables local attackers to manipulate the file system by leveraging symbolic links to delete arbitrary files that they would normally not have access to. The issue stems from the improper management of file paths during session cleanup operations, creating a privilege escalation vector through file system manipulation.
The technical implementation of this vulnerability occurs when systemd-logind processes user session termination and attempts to remove session-related files through the rm_rf_children function. During this cleanup process, the function does not properly validate or resolve symbolic links before attempting file operations, allowing a local attacker to create malicious symbolic links that point to sensitive system files. When the function processes these links, it follows the symbolic references and deletes the target files rather than the intended temporary files, effectively enabling arbitrary file deletion. This behavior aligns with CWE-367, which describes the dangerous use of a function that can be exploited to perform unintended file operations through symbolic link manipulation.
The operational impact of CVE-2012-1174 extends beyond simple file deletion capabilities, as it represents a significant privilege escalation vulnerability within the system's session management framework. An attacker with local access can leverage this flaw to remove critical system files, potentially leading to system instability, service disruption, or even complete system compromise. The vulnerability is particularly concerning because it operates within the login manager context, which typically runs with elevated privileges and has access to user session data. This attack vector can be exploited to remove configuration files, binaries, or other critical system components that are essential for proper system operation, making it a severe security concern for any system running affected versions of systemd.
Mitigation strategies for this vulnerability primarily focus on updating to systemd version 44 or later, where the problematic file handling logic has been corrected. System administrators should prioritize patching affected systems and monitoring for potential exploitation attempts through log analysis. Additional protective measures include implementing proper file system permissions, restricting local user access to sensitive directories, and monitoring session management processes for unusual file operations. From an ATT&CK framework perspective, this vulnerability maps to privilege escalation techniques and can be categorized under T1068, which involves the exploitation of legitimate credentials and system access for unauthorized operations. Organizations should also consider implementing automated patch management systems to ensure timely deployment of security updates and maintain comprehensive monitoring of system integrity to detect potential exploitation attempts.