CVE-2023-40343 in Tuleap Authentication Plugin
Summary
by MITRE • 08/16/2023
Jenkins Tuleap Authentication Plugin 1.1.20 and earlier uses a non-constant time comparison function when validating an authentication token allowing attackers to use statistical methods to obtain a valid authentication token.
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Analysis
by VulDB Data Team • 09/10/2023
The vulnerability identified as CVE-2023-40343 affects the Jenkins Tuleap Authentication Plugin version 1.1.20 and earlier, presenting a significant security risk through its implementation of authentication token validation. This flaw resides in the plugin's handling of authentication tokens, where it employs a non-constant time comparison function during the validation process. The issue stems from the plugin's failure to implement constant-time string comparison algorithms when verifying authentication tokens against expected values, creating a timing side-channel attack vector that can be exploited by malicious actors.
The technical implementation of this vulnerability involves the use of standard string comparison functions that execute in variable time based on the position of the first mismatched character. When an attacker attempts to brute force or guess a valid authentication token, they can observe the time variations in the plugin's response behavior. This timing information can be statistically analyzed to determine the correct characters in the token, effectively enabling credential stuffing or brute force attacks against the authentication mechanism. The vulnerability directly maps to CWE-203, which describes the exposure of information through timing discrepancies, and represents a classic example of a timing side-channel attack that violates fundamental security principles for cryptographic operations.
The operational impact of this vulnerability extends beyond simple authentication bypass scenarios, as it can enable attackers to systematically compromise user accounts within Jenkins environments that utilize the affected plugin. Attackers can leverage statistical analysis techniques to reduce the computational complexity of token guessing, transforming what would normally be a computationally infeasible brute force attack into a practical threat. This weakness particularly affects continuous integration and deployment pipelines that rely on Jenkins for automation, potentially allowing unauthorized access to build servers, code repositories, and deployment environments. The vulnerability also aligns with ATT&CK technique T1110.003, which covers credential guessing through the exploitation of timing side channels in authentication systems.
Organizations utilizing Jenkins with the Tuleap Authentication Plugin should immediately upgrade to version 1.1.21 or later, which implements proper constant-time comparison functions to address this vulnerability. Security teams should conduct comprehensive inventory assessments to identify all instances of the affected plugin across their Jenkins infrastructure, as the vulnerability may be present in multiple build servers or deployment environments. Additionally, organizations should consider implementing network-level monitoring to detect anomalous authentication patterns that might indicate timing-based attacks. The mitigation strategy should include regular security patch management processes, as well as the implementation of additional authentication layers such as multi-factor authentication to reduce the attack surface. Organizations should also review their Jenkins configurations to ensure that authentication tokens are properly rotated and that access controls are appropriately enforced to limit the potential impact of any successful exploitation attempts.