CVE-2003-0637 in iChain
Summary
by MITRE
Novell iChain 2.2 before Support Pack 1 uses a shorter timeout for a non-existent user than a valid user, which makes it easier for remote attackers to guess usernames and conduct brute force password guessing.
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Analysis
by VulDB Data Team • 06/15/2018
The vulnerability described in CVE-2003-0637 represents a classic timing attack scenario that exploits differences in response times between valid and invalid user authentication attempts within the Novell iChain 2.2 authentication system. This weakness stems from the implementation design where the system responds with different timing characteristics when processing authentication requests for non-existent versus valid user accounts. The fundamental flaw lies in the inconsistent response behavior that creates a distinguishable pattern for remote attackers to analyze and exploit.
The technical implementation of this vulnerability manifests through the authentication service's response handling mechanism that fails to maintain consistent timing regardless of whether the requested user account exists in the system database. When a remote attacker submits an authentication request, the system exhibits a measurable delay difference in its response time for non-existent user accounts compared to valid accounts. This timing discrepancy, though subtle, provides attackers with sufficient information to determine the existence of specific user accounts through systematic trial and error attempts.
The operational impact of this vulnerability extends beyond simple username enumeration as it fundamentally undermines the security of the authentication system by enabling automated brute force attacks. Attackers can leverage the timing differences to quickly identify valid user accounts and then focus their password guessing efforts on these confirmed accounts, dramatically reducing the time and resources required for successful unauthorized access. This vulnerability particularly affects systems where user account enumeration could lead to privilege escalation or further compromise of the authentication infrastructure.
From a cybersecurity perspective, this vulnerability aligns with CWE-203, which describes "Information Exposure Through Timing Discrepancy," and represents a clear violation of the principle of consistent response times in security-critical systems. The issue also maps to ATT&CK technique T1110.001, which covers "Brute Force: Password Guessing," as the timing information leak directly facilitates more efficient brute force attacks against the authentication system. Organizations implementing authentication systems must ensure that all authentication responses maintain consistent timing characteristics regardless of account validity to prevent such information leakage.
The mitigation strategy for this vulnerability requires implementing uniform response timing across all authentication attempts, ensuring that the system does not differentiate response times based on account existence. This typically involves modifying the authentication service to maintain consistent processing delays for all user verification attempts, regardless of whether the user exists in the system database. Additionally, implementing account lockout mechanisms and rate limiting for authentication attempts can further reduce the effectiveness of brute force attacks even if timing information leakage persists. The most effective approach involves comprehensive code review and testing of authentication response behaviors to ensure that no timing variations exist between valid and invalid account access attempts.