CVE-2018-1999045 in Jenkins
Summary
by MITRE
A improper authentication vulnerability exists in Jenkins 2.137 and earlier, 2.121.2 and earlier in SecurityRealm.java, TokenBasedRememberMeServices2.java that allows attackers with a valid cookie to remain logged in even if that feature is disabled.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 03/17/2020
This vulnerability resides in the authentication mechanism of Jenkins continuous integration and deployment platform, specifically within the SecurityRealm.java and TokenBasedRememberMeServices2.java components. The flaw represents a critical misconfiguration in the session management system that allows unauthorized access even when the remember me authentication feature has been explicitly disabled by administrators. The vulnerability affects Jenkins versions up to 2.137 and 2.121.2, indicating a widespread issue across multiple release branches. The technical implementation fails to properly validate whether the remember me functionality is enabled before processing authentication tokens, creating a bypass condition that undermines the security controls put in place by system administrators.
The operational impact of this vulnerability is significant as it directly compromises the principle of least privilege and authentication controls within Jenkins environments. Attackers who have obtained valid authentication cookies can maintain persistent access to the system regardless of administrative security settings. This represents a direct violation of the authentication model where disabling a feature should prevent its functionality from being exploited. The vulnerability enables what cybersecurity professionals would classify as an authentication bypass, allowing persistent unauthorized access that could go undetected for extended periods. Organizations using Jenkins for critical build and deployment processes face increased risk of unauthorized code changes, data manipulation, and potential lateral movement within their infrastructure.
Security implications extend beyond simple unauthorized access as this vulnerability aligns with attack patterns described in the MITRE ATT&CK framework under the credential access and persistence domains. The flaw essentially provides attackers with a method to maintain access even when standard authentication controls should prevent it, creating a persistent threat vector. From a CWE perspective, this vulnerability maps to CWE-287 which addresses improper authentication issues, specifically focusing on authentication bypass mechanisms. The root cause stems from inadequate input validation and state management within the authentication service, where the system fails to properly enforce configuration settings that govern authentication behavior.
Mitigation strategies should focus on immediate patching of affected Jenkins versions to the latest stable releases that contain the authentication fix. Administrators should also conduct thorough security audits of their Jenkins configurations to ensure that remember me functionality is properly disabled across all environments. Network segmentation and monitoring should be implemented to detect unusual authentication patterns and cookie usage that might indicate exploitation attempts. Additionally, organizations should review their overall authentication policies and implement multi-factor authentication where possible to reduce the impact of credential compromise. Regular security assessments and penetration testing should be conducted to identify similar configuration vulnerabilities in other components of the CI/CD pipeline that might present similar authentication bypass opportunities.