CVE-2020-2152 in Subversion Release Manager Plugin
Summary
by MITRE
Jenkins Subversion Release Manager Plugin 1.2 and earlier does not escape the error message for the Repository URL field form validation, resulting in a reflected cross-site scripting vulnerability.
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Analysis
by VulDB Data Team • 03/10/2020
The vulnerability identified as CVE-2020-2152 affects the Jenkins Subversion Release Manager Plugin version 1.2 and earlier, representing a critical security flaw that exposes systems to cross-site scripting attacks. This issue arises from improper input validation and output sanitization within the plugin's form validation mechanism, specifically targeting the Repository URL field. The vulnerability stems from the plugin's failure to properly escape error messages generated during form validation, creating an avenue for malicious actors to inject and execute arbitrary JavaScript code within the context of a victim's browser session. Such a flaw represents a significant risk to Jenkins environments where multiple users interact with the system, as it can be exploited to compromise user sessions and potentially escalate privileges.
The technical implementation of this vulnerability occurs when users attempt to submit a form containing an invalid Repository URL, triggering the plugin's validation process. During this process, the error message containing the malformed input is displayed without proper HTML escaping, allowing attackers to craft malicious inputs that include JavaScript payloads within the Repository URL field. When other users view the error message, their browsers execute the embedded scripts, leading to reflected cross-site scripting conditions. This vulnerability aligns with CWE-79 which specifically addresses cross-site scripting flaws, and demonstrates how insufficient output escaping in web applications can create persistent security weaknesses. The reflected nature of the attack means that the malicious script is executed from a web server's response to a user's input, making it particularly dangerous in collaborative environments where multiple users interact with shared Jenkins instances.
The operational impact of CVE-2020-2152 extends beyond simple script execution, as it can enable attackers to perform session hijacking, steal sensitive credentials, manipulate data within the Jenkins environment, and potentially gain unauthorized access to underlying systems. In enterprise environments where Jenkins serves as a central automation platform for continuous integration and deployment processes, this vulnerability could allow attackers to compromise build processes, access source code repositories, and manipulate deployment pipelines. The reflected XSS nature means that attackers can craft malicious URLs that, when clicked by authorized users, execute malicious code in their browsers, potentially leading to complete system compromise. This vulnerability also aligns with ATT&CK technique T1211 which covers exploitation of vulnerabilities in web applications, and T1566 which addresses social engineering through malicious links. Organizations using Jenkins with the affected plugin version face significant risk of unauthorized access and data compromise, particularly in environments where Jenkins is used for critical development and deployment workflows.
Mitigation strategies for CVE-2020-2152 should prioritize immediate plugin updates to version 1.3 or later, which contain the necessary fixes for proper input sanitization and output escaping. Organizations should implement comprehensive input validation policies that sanitize all user-provided data before processing, particularly for form fields that display error messages. Network-level protections such as web application firewalls can provide additional defense-in-depth measures, though they should not be considered a substitute for proper code-level fixes. Security teams should conduct thorough vulnerability assessments of all Jenkins plugins to identify similar issues, as this vulnerability demonstrates how seemingly minor input validation flaws can create major security risks. Regular security auditing of Jenkins configurations and plugin installations, along with implementation of principle of least privilege access controls, will help reduce the overall attack surface and limit potential damage from similar vulnerabilities. The fix implemented in the updated plugin version addresses the root cause by ensuring proper HTML escaping of error messages, preventing malicious payloads from being executed in user browsers while maintaining functional error reporting capabilities.