CVE-2015-20110 in generator-jhipster
Summary
by MITRE • 10/31/2023
JHipster generator-jhipster before 2.23.0 allows a timing attack against validateToken due to a string comparison that stops at the first character that is different. Attackers can guess tokens by brute forcing one character at a time and observing the timing. This of course drastically reduces the search space to a linear amount of guesses based on the token length times the possible characters.
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Analysis
by VulDB Data Team • 09/28/2025
The vulnerability identified as CVE-2015-20110 affects the JHipster generator-jhipster tool version 2.23.0 and earlier, presenting a critical timing attack vulnerability within the validateToken function. This flaw stems from an insecure string comparison implementation that terminates the validation process as soon as the first differing character is encountered, creating measurable timing differences that attackers can exploit. The vulnerability resides in the cryptographic token validation mechanism, which is fundamental to authentication and authorization processes within web applications generated by this tool.
The technical implementation of this vulnerability demonstrates a classic timing attack vector where the application's response time varies proportionally to the number of matching characters in the token being validated. When an attacker submits a malformed token, the system performs character-by-character comparison but stops execution immediately upon detecting the first mismatch, resulting in inconsistent response times that directly correlate to the correctness of characters in the token. This behavior creates a predictable timing pattern that can be measured and analyzed to determine valid token components incrementally. The vulnerability specifically impacts the cryptographic validation routine and exposes a weakness in the comparison algorithm that fails to implement constant-time string comparison techniques.
The operational impact of this vulnerability is severe and directly affects the security posture of applications generated by JHipster versions prior to 2.23.0. Attackers can systematically brute force tokens by testing individual characters at each position and measuring response times to determine valid token values, reducing the computational complexity from exponential to linear time complexity. This makes token guessing attacks significantly more feasible and dramatically reduces the effective entropy of authentication tokens, potentially compromising user sessions, API access, and other security-sensitive operations. The vulnerability affects the core authentication mechanisms and undermines the trust model of applications built with this tool.
The vulnerability maps directly to CWE-208, which specifically addresses timing attacks that occur when the time taken to perform operations varies based on input values. It also aligns with ATT&CK technique T1212, which covers exploitation of information disclosure vulnerabilities through timing analysis. The issue represents a failure to implement constant-time comparison algorithms, a well-documented security best practice that prevents timing side-channel attacks. Organizations using affected JHipster versions should immediately upgrade to 2.23.0 or later, which implements proper constant-time string comparison mechanisms. Additionally, security teams should conduct comprehensive vulnerability assessments of all applications generated by affected versions and consider implementing additional monitoring for anomalous authentication patterns that may indicate timing attack attempts. The remediation involves replacing the vulnerable string comparison logic with implementations that maintain consistent execution time regardless of input values, ensuring that cryptographic validation operations do not leak information through timing variations.