CVE-2012-1111 in lightdm
Summary
by MITRE
lightdm before 1.0.9 does not properly close file descriptors before opening a child process, which allows local users to write to the lightdm log or have other unspecified impact.
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Analysis
by VulDB Data Team • 04/03/2022
The vulnerability identified as CVE-2012-1111 affects lightdm versions prior to 1.0.9 and represents a critical security flaw in the display manager's process management. This issue stems from improper file descriptor handling during the execution of child processes, creating a window of opportunity for local attackers to exploit the system. The vulnerability falls under the category of improper resource cleanup and process management, which is classified as CWE-110 in the Common Weakness Enumeration catalog. The flaw occurs when the lightdm daemon fails to properly close file descriptors before invoking child processes, leaving these descriptors accessible to the newly spawned processes.
The technical implementation of this vulnerability allows local users to manipulate file descriptor inheritance, enabling them to write to the lightdm log files or potentially achieve other unspecified impacts. When lightdm executes child processes without properly closing file descriptors, these descriptors are inherited by the child processes, creating potential security implications. The inherited file descriptors may point to sensitive system resources, log files, or other critical components that could be manipulated by the attacker. This type of vulnerability is particularly dangerous in display manager contexts where elevated privileges are often required for authentication and session management operations.
The operational impact of CVE-2012-1111 extends beyond simple log manipulation, as it represents a broader class of privilege escalation vulnerabilities that can be leveraged by local attackers. Attackers could potentially use this flaw to gain unauthorized access to system resources, manipulate authentication logs, or even escalate privileges to gain root access on affected systems. The vulnerability is particularly concerning in multi-user environments where local users might attempt to exploit the flaw to gain unauthorized access to system resources or compromise the integrity of the authentication process. This weakness aligns with several tactics described in the MITRE ATT&CK framework, specifically those related to privilege escalation and persistence through system-level modifications.
The remediation for this vulnerability requires updating lightdm to version 1.0.9 or later, where proper file descriptor management has been implemented. System administrators should also consider implementing additional security controls such as monitoring for unusual log file modifications and ensuring that file descriptor inheritance is properly managed across all system processes. The vulnerability demonstrates the importance of proper process management and resource cleanup in security-critical applications, particularly those handling authentication and session management functions. Organizations should conduct regular vulnerability assessments to identify similar issues in other display managers and system components that might be susceptible to similar file descriptor inheritance problems.