CVE-2003-0692 in KDE
Summary
by MITRE
KDM in KDE 3.1.3 and earlier uses a weak session cookie generation algorithm that does not provide 128 bits of entropy, which allows attackers to guess session cookies via brute force methods and gain access to the user session.
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Analysis
by VulDB Data Team • 06/29/2021
The vulnerability described in CVE-2003-0692 represents a critical weakness in the KDE Display Manager KDM version 3.1.3 and earlier implementations. This issue fundamentally undermines the security of graphical login sessions by employing a session cookie generation algorithm that fails to meet minimum cryptographic requirements for entropy. The flaw exists within the core authentication infrastructure of KDE desktop environments, making it particularly dangerous as it affects the initial point of system access for users. The weak entropy generation creates predictable session identifiers that can be exploited through systematic brute force attacks, potentially allowing unauthorized users to hijack active sessions and gain full access to target systems.
The technical implementation of this vulnerability stems from the insufficient entropy in the session cookie generation process, which is classified under CWE-330 as the use of insufficiently random values. The algorithm fails to produce cookies with the required 128 bits of entropy, making the session identifiers vulnerable to prediction and enumeration attacks. This weakness specifically impacts the KDM component of KDE, which serves as the display manager responsible for handling user authentication and session management. The lack of proper cryptographic randomness in session cookie generation creates a direct pathway for attackers to bypass normal authentication mechanisms through automated guessing techniques, effectively undermining the entire session management framework.
From an operational perspective, this vulnerability presents significant risks to system security and user privacy. Attackers can systematically guess session cookies without requiring additional credentials or exploiting other system weaknesses, making the attack surface extremely broad and accessible. The impact extends beyond individual user sessions to potentially compromise entire desktop environments, especially in multi-user systems where session hijacking could lead to unauthorized access to sensitive data and system resources. This vulnerability directly aligns with ATT&CK technique T1548.003 for bypassing system access controls and represents a classic example of insufficient entropy in cryptographic implementations that enables session hijacking attacks.
The recommended mitigations for this vulnerability include immediate upgrading to KDE versions that address the weak session cookie generation algorithm, typically KDE 3.1.4 and later releases. Organizations should implement additional security measures such as rate limiting for authentication attempts, monitoring for suspicious session activity, and ensuring proper entropy sources are available in the operating system. System administrators should also consider implementing network-level protections such as firewalls to limit access to KDM services and employ intrusion detection systems to monitor for brute force attempts. The fix addresses the root cause by implementing proper cryptographic random number generation that meets minimum entropy requirements, ensuring that session identifiers cannot be predicted through brute force methods. This vulnerability underscores the critical importance of proper entropy implementation in security-critical components and demonstrates how seemingly minor implementation flaws can create significant security risks in authentication systems.