CVE-2003-1324 in Elm ME+
Summary
by MITRE
Race condition in the can_open function in Elm ME+ 2.4, when installed setgid mail and the operating system lacks POSIX saved ID support, allows local users to read and modify certain files with the privileges of the mail group.
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Analysis
by VulDB Data Team • 07/04/2017
The vulnerability identified as CVE-2003-1324 represents a critical race condition flaw within the can_open function of Elm ME+ version 2.4. This issue specifically manifests when the software is installed with setgid mail permissions and the underlying operating system does not support POSIX saved ID functionality. The fundamental weakness lies in how the application handles file access permissions during the opening process, creating a temporal window where security checks can be bypassed. The race condition occurs between the time when the application checks file permissions and when it actually opens the file, allowing malicious local users to exploit this temporal gap for privilege escalation.
The technical implementation of this vulnerability stems from the absence of proper synchronization mechanisms within the can_open function. When Elm ME+ operates with setgid mail privileges, it should maintain elevated permissions to access mail-related files. However, the race condition allows attackers to manipulate file paths or contents between permission checks and actual file operations. This flaw directly relates to CWE-362, which categorizes race conditions as a common weakness in software security where the timing of operations creates exploitable vulnerabilities. The vulnerability is particularly dangerous because it leverages the inherent trust model of setgid applications, where legitimate system processes can be subverted to perform actions with elevated privileges.
The operational impact of this vulnerability extends beyond simple privilege escalation, as local users can effectively bypass the normal access controls that protect sensitive mail files and system resources. Attackers can read confidential mail messages, modify mail queues, or potentially inject malicious content into the mail system. The exploitation requires local system access but provides significant privileges that can compromise the integrity and confidentiality of the entire mail subsystem. This vulnerability demonstrates how insufficient consideration of timing-related security issues can create persistent backdoors within system applications, particularly those designed to operate with elevated privileges for legitimate administrative purposes.
Mitigation strategies for CVE-2003-1324 should focus on addressing the underlying race condition through proper synchronization mechanisms and ensuring that applications properly handle privilege transitions. System administrators should immediately update to patched versions of Elm ME+ or apply appropriate workarounds such as removing setgid permissions where possible. The solution must implement atomic file operations or proper locking mechanisms to prevent the temporal window that enables exploitation. Additionally, this vulnerability highlights the importance of adhering to security best practices outlined in the ATT&CK framework, specifically addressing privilege escalation techniques that exploit timing-related weaknesses in system applications. Organizations should conduct comprehensive audits of setgid applications and ensure that all system components properly implement POSIX compliance when dealing with saved ID functionality, as this vulnerability represents a classic example of how missing security controls in Unix-like systems can create persistent threats.