CVE-2019-1003003 in Jenkins
Summary
by MITRE
An improper authorization vulnerability exists in Jenkins 2.158 and earlier, LTS 2.150.1 and earlier in core/src/main/java/hudson/security/TokenBasedRememberMeServices2.java that allows attackers with Overall/RunScripts permission to craft Remember Me cookies that would never expire, allowing e.g. to persist access to temporarily compromised user accounts.
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Analysis
by VulDB Data Team • 05/04/2020
This vulnerability resides in the core authentication mechanism of Jenkins, specifically within the TokenBasedRememberMeServices2.java component that handles remember me functionality for user sessions. The flaw represents a critical authorization bypass that allows malicious actors with minimal privileges to escalate their access privileges indefinitely. The vulnerability affects Jenkins versions up to 2.158 and LTS versions up to 2.150.1, making it a widespread concern across numerous installations. Attackers with Overall/RunScripts permission can exploit this weakness to create persistent authentication tokens that remain valid indefinitely, effectively bypassing normal session expiration mechanisms that should terminate access after a set period of inactivity.
The technical implementation flaw stems from improper validation of remember me cookie tokens within the authentication flow. When users select the "Remember Me" option, Jenkins generates tokens that should typically expire after a predetermined timeframe. However, the vulnerability allows attackers to manipulate these tokens in such a way that they never expire, creating a persistent backdoor into the system. This occurs because the token validation logic fails to properly enforce expiration constraints, enabling attackers to craft tokens that bypass normal security checks. The vulnerability is particularly dangerous because it operates at the core authentication layer, making it difficult to detect and trace through standard monitoring mechanisms.
The operational impact of this vulnerability extends far beyond simple privilege escalation, as it enables attackers to maintain persistent access to compromised accounts long after initial exploitation. This persistent access allows for extended reconnaissance, data exfiltration, and further lateral movement within the network. Organizations using Jenkins for continuous integration and deployment pipelines face significant risk, as compromised credentials can lead to unauthorized code deployments, access to sensitive source code repositories, and potential compromise of entire build infrastructures. The vulnerability also affects the integrity of audit trails, as attackers can maintain access without detection, undermining the security posture of CI/CD environments that rely heavily on Jenkins.
Mitigation strategies should begin with immediate patching of affected Jenkins installations to versions 2.159 and later for the main release, or 2.150.2 and later for LTS versions. Organizations should also implement additional monitoring of authentication token usage patterns to detect anomalous behavior that might indicate exploitation attempts. Security teams should review and restrict permissions for users with Overall/RunScripts access, implementing the principle of least privilege to minimize the impact of potential compromises. Network segmentation and additional authentication layers such as multi-factor authentication should be considered as additional protective measures. This vulnerability aligns with CWE-284 which addresses improper access control, and maps to ATT&CK technique T1078 for valid accounts, as it enables attackers to maintain persistent access through legitimate authentication mechanisms. Organizations should also conduct comprehensive security audits of their Jenkins installations to identify other potential vulnerabilities in their CI/CD infrastructure that could be exploited in conjunction with this authentication bypass.