CVE-2012-5638 in SANLock
Summary
by MITRE
The setup_logging function in log.h in SANLock uses world-writable permissions for /var/log/sanlock.log, which allows local users to overwrite the file content or bypass intended disk-quota restrictions via standard filesystem write operations.
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Analysis
by VulDB Data Team • 04/14/2019
The vulnerability identified as CVE-2012-5638 resides within the SANLock logging mechanism, specifically in the setup_logging function located in log.h. This flaw represents a critical security oversight that directly impacts the integrity and confidentiality of system logging operations. SANLock, a distributed lock manager designed for storage environments, employs this logging functionality to maintain operational visibility and diagnostic information. The core issue manifests when the logging system creates the /var/log/sanlock.log file with world-writable permissions, creating an exploitable condition that undermines fundamental security principles of file system access controls.
The technical implementation flaw stems from improper permission handling during log file creation, where the setup_logging function fails to establish appropriate access controls for the target log file. This vulnerability operates under CWE-732, which specifically addresses inadequate permissions for critical security resources, and aligns with ATT&CK technique T1562.006 for privilege escalation through file permissions. The world-writable permission setting allows any local user on the system to perform write operations against the log file, effectively enabling malicious actors to manipulate the logging data or disrupt normal system operations. This misconfiguration creates a pathway for attackers to either overwrite critical log entries that might contain security-relevant information or to bypass disk quota restrictions that are typically enforced through proper file system permissions.
The operational impact of this vulnerability extends beyond simple data manipulation, as it fundamentally compromises the integrity of system audit trails and monitoring capabilities. Local users can exploit this weakness to inject false log entries, potentially obscuring malicious activities or creating false narratives within the system's operational history. Additionally, the ability to bypass disk quota restrictions through file overwrites can lead to denial-of-service conditions where legitimate system processes are unable to write to the log file due to space constraints. This vulnerability directly affects the availability and reliability of logging services, which are essential for security monitoring, incident response, and compliance auditing. The compromised logging mechanism undermines the trustworthiness of the entire SANLock system and can provide attackers with opportunities to conduct stealthy operations while avoiding detection through log manipulation.
Mitigation strategies for CVE-2012-5638 require immediate implementation of proper file permission controls for log files. System administrators should ensure that the /var/log/sanlock.log file is created with restrictive permissions, typically owned by the appropriate system user with read/write access limited to authorized processes. The fix involves modifying the setup_logging function to explicitly set secure file permissions during log file creation, preventing world-writable access. Organizations should also implement regular permission audits to identify and remediate similar issues across their infrastructure. This vulnerability highlights the importance of following secure coding practices and proper access control implementation, particularly for security-critical system components. The remediation process should include comprehensive testing to ensure that logging functionality remains operational while maintaining appropriate security controls. Additionally, system hardening procedures should be updated to include checks for world-writable files in critical logging directories, preventing similar vulnerabilities from being introduced in future software versions.