CVE-2022-23541 in jsonwebtoken
Summary
by MITRE • 12/22/2022
jsonwebtoken is an implementation of JSON Web Tokens. Versions `
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Analysis
by VulDB Data Team • 01/22/2023
The jsonwebtoken library represents a widely adopted Node.js implementation for creating and verifying JSON Web Tokens that serves as a cornerstone for authentication and authorization mechanisms across numerous web applications and APIs. This particular vulnerability affects the library's handling of token verification processes, specifically when dealing with tokens that contain certain malformed or unexpected payload structures. The flaw manifests in how the library processes the audience claim within JWTs, creating a potential security bypass that could allow unauthorized access to protected resources. The vulnerability stems from insufficient input validation during the token verification phase, where the library fails to properly sanitize or validate the audience parameter before proceeding with the verification logic. This weakness creates an opportunity for attackers to manipulate JWT claims in ways that circumvent intended security controls, particularly when the application relies on audience validation as part of its authentication flow.
The technical exploitation of this vulnerability occurs when an attacker crafts a JWT with a malicious audience value that passes through the library's verification routine without proper validation. The flaw exists in the library's processing of the audience parameter, where it accepts certain malformed values that should trigger verification failures but instead proceed with successful validation. This behavior creates a path for privilege escalation or unauthorized access, as the system may incorrectly grant access based on a forged audience claim that bypasses intended security boundaries. The vulnerability is particularly concerning because it operates at the token verification level, meaning that applications using this library may accept tokens that should have been rejected due to improper audience validation. The root cause of this issue can be traced to improper input sanitization and inadequate boundary checking within the verification function, which allows unexpected values to propagate through the security validation chain.
The operational impact of CVE-2022-23541 extends beyond simple authentication bypasses to potentially enable broader system compromise when applications rely on audience validation as part of their security architecture. Attackers could exploit this vulnerability to gain access to resources intended for specific audiences or applications, effectively breaking the intended isolation between different system components or user groups. The vulnerability affects any application using vulnerable versions of the jsonwebtoken library, making it particularly dangerous given the library's widespread adoption across the Node.js ecosystem. Organizations may experience unauthorized access to sensitive data, privilege escalation, or unauthorized system operations when this vulnerability is exploited in environments where audience validation serves as a security control. The impact is further amplified because many applications may not explicitly test for this specific validation scenario, meaning that the vulnerability could remain undetected until an attacker successfully exploits it. This type of vulnerability aligns with CWE-20, which addresses improper input validation, and represents a classic example of how seemingly minor validation gaps can create significant security risks.
Mitigation strategies for this vulnerability require immediate updates to the jsonwebtoken library to versions that address the specific audience validation issue. Organizations should conduct comprehensive vulnerability assessments to identify all applications and services using affected library versions, as the vulnerability may be present in various components of the application stack. The recommended approach involves upgrading to patched versions of the library while implementing additional runtime checks to validate audience claims before they are processed by the library. Security teams should also consider implementing monitoring and logging for unusual audience claim patterns that might indicate exploitation attempts. Additionally, organizations should review their application's token handling logic to ensure that audience validation is properly implemented at multiple layers of the security architecture, rather than relying solely on the library's built-in validation. The ATT&CK framework categorizes this type of vulnerability under privilege escalation techniques, specifically targeting authentication mechanisms that should enforce access control boundaries. Regular security testing and dependency monitoring should be implemented to prevent similar vulnerabilities from emerging in other components of the application ecosystem, as this vulnerability demonstrates how library-level flaws can cascade into system-wide security issues.