CVE-2024-25190 in l8w8jwt
Summary
by MITRE • 02/08/2024
l8w8jwt 2.2.1 uses memcmp (which is not constant time) to verify authentication, which makes it easier to bypass authentication via a timing side channel.
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Analysis
by VulDB Data Team • 08/19/2024
The vulnerability identified as CVE-2024-25190 affects the l8w8jwt library version 2.2.1 and represents a critical security flaw that undermines the integrity of authentication mechanisms through timing side channel attacks. This library is commonly used for JSON Web Token processing in various web applications and systems, making the vulnerability particularly concerning for organizations relying on JWT-based authentication. The flaw stems from the library's implementation of authentication verification using the standard memcmp function, which does not provide constant-time execution characteristics essential for secure cryptographic operations.
The technical root cause of this vulnerability lies in the use of memcmp for comparing authentication tokens or signatures, which exposes the system to timing attacks that can be exploited by malicious actors. When memcmp performs string comparison, it processes characters sequentially and returns immediately upon detecting a mismatch, creating observable time differences that can be measured and analyzed. This timing variation provides attackers with information about the correct authentication data, enabling them to gradually deduce valid credentials or tokens through repeated testing attempts. The vulnerability directly maps to CWE-208, which specifically addresses timing side channels that can reveal information about cryptographic keys or authentication data through timing variations in program execution.
From an operational perspective, this vulnerability creates significant risk for systems implementing JWT-based authentication, as attackers can systematically exploit the timing differences to bypass authentication mechanisms without requiring brute force computation resources. The attack surface extends to any application that utilizes the affected l8w8jwt library for token validation, potentially compromising user accounts, access controls, and sensitive system resources. The vulnerability's impact is amplified because timing attacks can often be executed remotely and may not require extensive computational resources, making them particularly attractive to threat actors seeking to compromise authentication systems. This weakness aligns with ATT&CK technique T1212, which describes exploitation of software vulnerabilities that rely on timing information to bypass security controls.
Organizations should immediately prioritize updating their systems to use a patched version of the l8w8jwt library that implements constant-time comparison functions such as memcmp_s or custom constant-time comparison routines that do not expose timing variations. The mitigation strategy should also include implementing additional security controls such as rate limiting, account lockout mechanisms, and monitoring for unusual authentication patterns that might indicate timing attack attempts. Security teams should conduct comprehensive vulnerability assessments to identify all systems utilizing the affected library and ensure proper patch management procedures are in place to prevent similar vulnerabilities in other cryptographic implementations. The remediation process must also include reviewing other cryptographic functions within the application stack to ensure similar timing vulnerabilities do not exist in other components that might be susceptible to side channel attacks.