CVE-2005-2494 in KDE
Summary
by MITRE
kcheckpass in KDE 3.2.0 up to 3.4.2 allows local users to gain root access via a symlink attack on lock files.
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Analysis
by VulDB Data Team • 06/30/2025
The vulnerability identified as CVE-2005-2494 represents a critical privilege escalation flaw within the KDE desktop environment, specifically affecting versions 3.2.0 through 3.4.2. This issue resides in the kcheckpass utility which serves as a component responsible for authenticating users during system operations. The vulnerability stems from inadequate handling of temporary files and lock mechanisms, creating a pathway for local attackers to manipulate system security controls. The flaw operates through a classic symlink attack vector where malicious users can exploit the predictable naming patterns of lock files to gain unauthorized root privileges.
The technical implementation of this vulnerability involves the kcheckpass utility's improper management of lock file creation and validation processes. When the utility attempts to create or verify lock files during authentication procedures, it does not properly validate the symbolic links in the file system path. This behavior creates a race condition scenario where an attacker can establish a symbolic link pointing to a critical system file such as /etc/shadow or /etc/passwd before the legitimate process creates its intended lock file. The system then proceeds to write authentication data to the attacker-controlled location, effectively allowing privilege escalation to root level access.
From an operational impact perspective, this vulnerability presents a significant security risk to systems running affected KDE versions, particularly in multi-user environments where local access is possible. The attack requires local system access but does not need network connectivity or complex exploitation techniques. The vulnerability aligns with CWE-367, which describes the "Time-of-Check to Time-of-Use (TOCTOU) vulnerability" pattern, where the system's behavior changes between the time of validation and the time of actual use. This weakness enables attackers to manipulate the system state during the brief window between file checks and file operations, making it particularly dangerous in environments where multiple processes might interact with the same resources.
The attack vector for this vulnerability follows established patterns documented in the MITRE ATT&CK framework under techniques related to privilege escalation and local exploitation. Specifically, it maps to the T1068 "Exploitation for Privilege Escalation" and T1548.001 "Abuse Elevation Control Mechanism" categories, as it exploits the system's authentication mechanisms to gain elevated privileges. The vulnerability demonstrates how seemingly minor implementation flaws in system utilities can create substantial security risks, particularly when dealing with authentication and privilege management components.
Mitigation strategies for CVE-2005-2494 require immediate system updates to patched versions of KDE, as the vulnerability cannot be effectively addressed through configuration changes alone. System administrators should prioritize patching affected KDE installations and verify that no symbolic links exist in critical system paths that could be exploited. Additional protective measures include implementing proper file system permissions, using secure temporary file creation methods that prevent symbolic link manipulation, and monitoring for unauthorized file system changes in authentication-related directories. The vulnerability also highlights the importance of following secure coding practices that prevent TOCTOU race conditions through atomic file operations and proper file validation mechanisms. Organizations should conduct comprehensive audits of their KDE installations to ensure all systems are updated to versions that address this specific vulnerability and related privilege escalation risks.