CVE-2020-2238 in Git Parameter Plugin
Summary
by MITRE
Jenkins Git Parameter Plugin 0.9.12 and earlier does not escape the repository field on the 'Build with Parameters' page, resulting in a stored cross-site scripting (XSS) vulnerability exploitable by attackers with Job/Configure permission.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 11/12/2020
The vulnerability identified as CVE-2020-2238 affects the Jenkins Git Parameter Plugin version 0.9.12 and earlier, representing a critical security flaw that enables stored cross-site scripting attacks through improper input sanitization. This issue specifically manifests in the 'Build with Parameters' page where the repository field fails to implement adequate output escaping mechanisms, creating an exploitable vector for malicious actors who possess the Job/Configure permission level within the Jenkins environment.
The technical flaw resides in the plugin's failure to properly sanitize user-supplied input within the repository parameter field, which is rendered directly on the web interface without appropriate HTML escaping or encoding. When a malicious user with sufficient privileges configures a job parameter containing crafted malicious script code within the repository field, this content gets stored persistently within the Jenkins system and subsequently executed whenever the 'Build with Parameters' page is accessed by other users. This stored XSS vulnerability operates through the standard web application security pattern where user-controllable data is embedded into web pages without proper sanitization, allowing attackers to inject executable JavaScript code that executes in the context of other users' browsers.
The operational impact of this vulnerability extends beyond simple script execution, as it provides attackers with the ability to perform session hijacking, steal sensitive credentials, manipulate Jenkins job configurations, and potentially escalate privileges within the build environment. The vulnerability's exploitation requires minimal prerequisites since it only necessitates the Job/Configure permission level, which is often granted to developers and build operators within typical Jenkins deployments. This low barrier to entry makes the vulnerability particularly dangerous in environments where multiple users have administrative or configuration rights to Jenkins jobs, as any compromised account with these permissions could be leveraged to compromise the entire Jenkins instance.
Organizations affected by this vulnerability should immediately implement mitigations including upgrading to Jenkins Git Parameter Plugin version 0.9.13 or later, which contains the necessary patches to properly escape repository field content. Additional defensive measures should include implementing Content Security Policy headers to limit script execution capabilities, restricting user permissions to minimize the attack surface, and conducting regular security audits of Jenkins configurations. From an industry standards perspective, this vulnerability maps to CWE-79 (Cross-site Scripting) and aligns with ATT&CK technique T1059.007 (Command and Scripting Interpreter: JavaScript), highlighting the importance of input validation and output escaping in web application security frameworks. The vulnerability also demonstrates the critical need for proper security testing of plugins and third-party components within CI/CD environments, as insecure plugin implementations can compromise the entire build infrastructure and potentially lead to supply chain attacks that affect multiple downstream systems.