CVE-2017-10862 in jwt-scala
Summary
by MITRE
jwt-scala 1.2.2 and earlier fails to verify token signatures correctly which may lead to an attacker being able to pass specially crafted JWT data as a correctly signed token.
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Analysis
by VulDB Data Team • 11/24/2019
The vulnerability identified as CVE-2017-10862 affects jwt-scala versions 1.2.2 and earlier, representing a critical security flaw in JSON Web Token signature verification mechanisms. This issue stems from improper implementation of cryptographic signature validation within the scala-based jwt library, creating a fundamental weakness in the authentication and authorization framework. The flaw allows malicious actors to exploit the library's insufficient validation logic to forge tokens that appear authentic to the system, undermining the core security guarantees that JWTs are designed to provide.
The technical root cause of this vulnerability lies in the library's failure to properly validate digital signatures associated with JSON Web Tokens. When a JWT is generated, it includes a signature component that should be verified against the token's contents to ensure authenticity and integrity. In vulnerable versions of jwt-scala, the signature verification process was either completely bypassed or implemented incorrectly, allowing attackers to manipulate the token data while maintaining a valid signature format. This weakness falls under the broader category of cryptographic weakness vulnerabilities as classified by CWE-310, specifically addressing improper implementation of cryptographic primitives.
The operational impact of this vulnerability is severe and far-reaching across any system utilizing the affected jwt-scala library for authentication and authorization purposes. An attacker who successfully exploits this flaw can bypass authentication mechanisms by crafting malicious JWT tokens that the system accepts as legitimate. This could enable unauthorized access to protected resources, privilege escalation, data exfiltration, and complete compromise of systems relying on JWT-based authentication. The vulnerability is particularly dangerous because it operates at the authentication layer, potentially allowing attackers to impersonate legitimate users or even administrative accounts within the affected applications.
Systems implementing the vulnerable jwt-scala library are at significant risk of unauthorized access and data breaches. Organizations using this library in web applications, API gateways, or microservices architectures face potential exposure to attackers who can exploit this weakness to gain unauthorized access to sensitive data and functionality. The attack surface extends beyond individual applications to encompass entire ecosystems where JWT tokens are used for session management, API authentication, and service-to-service communication. According to ATT&CK framework, this vulnerability maps to privilege escalation and credential access techniques, as attackers can leverage forged tokens to bypass authentication controls and assume legitimate user identities within the target environment.
The recommended mitigation strategy involves immediate upgrade to jwt-scala version 1.2.3 or later, which contains the necessary fixes for proper signature verification. Organizations should also implement comprehensive security testing including penetration testing and code review processes to identify any other potential cryptographic weaknesses in their authentication systems. Additionally, implementing proper token validation mechanisms, monitoring for suspicious authentication patterns, and establishing robust key management practices can help reduce the overall risk exposure. Security teams should also consider implementing additional layers of authentication such as multi-factor authentication to provide defense-in-depth against potential exploitation of this and similar vulnerabilities.