CVE-2012-4524 in xlockmore
Summary
by MITRE
xlockmore before 5.43 'dclock' security bypass vulnerability
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Analysis
by VulDB Data Team • 02/26/2024
The CVE-2012-4524 vulnerability represents a significant security flaw in xlockmore versions prior to 5.43, specifically affecting the dclock module implementation. This vulnerability allows attackers to bypass authentication mechanisms through a carefully crafted sequence of operations that exploit a design flaw in how the screen locking system handles time-based authentication checks. The issue stems from insufficient validation of time synchronization states during the locking process, creating a window where unauthorized users can gain access to systems protected by xlockmore's dclock feature. The vulnerability affects Unix-like operating systems that utilize the xlockmore package for screen locking functionality, particularly those relying on the dclock module for time-based authentication mechanisms.
The technical root cause of this vulnerability lies in the improper handling of time synchronization checks within the dclock module implementation. When xlockmore initializes the dclock security feature, it fails to properly validate the time source before accepting authentication requests. This design flaw creates a race condition where an attacker can manipulate the system clock or time synchronization state to bypass the security checks that should prevent unauthorized access. The vulnerability specifically manifests when the system attempts to verify time-based authentication credentials, allowing attackers to exploit a logic flaw in the time validation routine that should have prevented access during certain time intervals. This issue is classified under CWE-284, which deals with improper access control, and more specifically relates to CWE-362, which addresses race conditions that can lead to security vulnerabilities.
The operational impact of CVE-2012-4524 extends beyond simple unauthorized access, as it represents a fundamental breakdown in the security model of screen locking systems. Attackers can leverage this vulnerability to gain access to locked systems without proper authentication, potentially compromising sensitive data stored on the device. The vulnerability is particularly concerning in enterprise environments where xlockmore is commonly used for workstation security, as it could allow unauthorized personnel to access confidential information or perform privileged operations. The attack vector requires minimal sophistication, as it exploits inherent flaws in the software's time validation logic rather than requiring complex exploitation techniques. This makes the vulnerability particularly dangerous as it can be exploited by users with basic system access, potentially leading to data breaches or system compromise. The vulnerability also impacts compliance with security standards such as those outlined in the NIST SP 800-53 framework, which requires robust access control mechanisms for protected systems.
Mitigation strategies for CVE-2012-4524 primarily focus on immediate software updates to xlockmore version 5.43 or later, which contains the necessary patches to address the time validation logic flaw. System administrators should also implement additional monitoring to detect unauthorized access attempts and ensure proper time synchronization across all systems. The patch addresses the vulnerability by strengthening the time validation routines and eliminating the race condition that allowed bypass of authentication checks. Organizations should also consider implementing time synchronization services such as NTP or similar protocols to maintain accurate system clocks, as the vulnerability's exploitation often relies on manipulating time-related system states. Additionally, security teams should review their access control policies and ensure that screen locking mechanisms are properly configured to prevent unauthorized access. The mitigation approach aligns with ATT&CK technique T1562.001, which involves disabling or modifying system security tools, and addresses the broader category of privilege escalation techniques that could be employed through such vulnerabilities. Regular security audits should verify that all systems using xlockmore have been updated and that appropriate access controls remain in place to prevent exploitation of similar vulnerabilities.