CVE-2021-35342 in Mender Enterprise
Summary
by MITRE • 08/27/2021
The useradm service 1.14.0 (in Northern.tech Mender Enterprise 2.7.x before 2.7.1) and 1.13.0 (in Northern.tech Mender Enterprise 2.6.x before 2.6.1) allows users to access the system with their JWT token after logout, because of missing invalidation (if the JWT verification cache is enabled).
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Analysis
by VulDB Data Team • 09/01/2021
The vulnerability identified as CVE-2021-35342 affects the useradm service within Northern.tech Mender Enterprise versions 2.6.x and 2.7.x, specifically impacting versions 1.13.0 and 1.14.0 respectively. This security flaw represents a critical session management weakness that undermines the authentication mechanism of the platform, creating persistent access risks for authenticated users. The issue manifests when users attempt to access system resources using their JSON Web Token (JWT) credentials after having logged out, indicating a failure in proper session termination and token invalidation processes.
The technical root cause of this vulnerability stems from the absence of proper JWT token invalidation within the useradm service implementation. When JWT verification caching is enabled, the system maintains cached authentication states that should be cleared upon user logout but are not being properly invalidated. This creates a window of opportunity where previously authenticated sessions remain valid even after explicit logout operations, effectively allowing unauthorized access to system resources through cached tokens. The flaw operates at the application level authentication layer and specifically impacts the session lifecycle management functionality, making it a direct violation of standard secure authentication practices.
From an operational impact perspective, this vulnerability creates significant security risks for organizations using Mender Enterprise platforms. Attackers who gain access to valid JWT tokens can continue to access system resources even after legitimate users have logged out, potentially leading to data breaches, unauthorized system modifications, and privilege escalation attacks. The vulnerability affects the core authentication service and could compromise the integrity of the entire platform's access control mechanisms, particularly in enterprise environments where multiple users interact with the system. This issue directly relates to CWE-613, which addresses insufficient session expiration and the improper handling of authentication tokens.
The security implications extend beyond simple unauthorized access to include potential lateral movement within the system and data exfiltration capabilities. Organizations using affected versions of Mender Enterprise may experience compromised user sessions, unauthorized device management operations, and potential escalation of privileges. The vulnerability's impact is particularly concerning in environments where sensitive device management operations occur, as attackers could maintain persistent access to critical infrastructure components. This weakness aligns with ATT&CK technique T1566, which covers credential harvesting through the exploitation of authentication bypass vulnerabilities.
Mitigation strategies for this vulnerability include immediate patching to versions 2.6.1 and 2.7.1 where the JWT token invalidation mechanism has been properly implemented. Organizations should also implement monitoring for unusual access patterns and ensure that JWT caching mechanisms are properly configured with appropriate expiration times. System administrators should review and validate session management policies, enforce strict token invalidation procedures upon logout, and consider implementing additional authentication layers such as multi-factor authentication to reduce the impact of token-based attacks. The fix addresses the fundamental flaw in session management by ensuring that cached JWT tokens are properly invalidated when users log out, thereby preventing the reuse of stale authentication credentials.