CVE-2020-2175 in FitNesse Plugin
Summary
by MITRE
Jenkins FitNesse Plugin 1.31 and earlier does not correctly escape report contents before showing them on the Jenkins UI, resulting in a stored cross-site scripting (XSS) vulnerability exploitable by users able to control the XML input files processed by the plugin.
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Analysis
by VulDB Data Team • 04/08/2020
The vulnerability identified as CVE-2020-2175 affects the Jenkins FitNesse Plugin version 1.31 and earlier, presenting a critical stored cross-site scripting flaw that enables attackers to execute malicious scripts within the Jenkins user interface. This issue arises from inadequate input sanitization when processing XML content that the plugin handles, creating a persistent XSS vector that can be exploited by malicious actors with the ability to influence the XML input files. The vulnerability specifically manifests when the plugin displays report contents in the Jenkins UI without proper HTML escaping, allowing attackers to inject malicious payloads that persist across user sessions.
The technical implementation of this vulnerability stems from the plugin's failure to properly sanitize user-controlled XML data before rendering it in the web interface. When FitNesse reports are processed and displayed within Jenkins, the plugin does not adequately escape special HTML characters or JavaScript code that might be present in the XML input. This lack of input validation and output encoding creates an environment where attackers can embed malicious scripts within the XML content, which then executes whenever other users view the affected reports in the Jenkins UI. The stored nature of this vulnerability means that the malicious payloads remain persistent in the system until manually removed, making it particularly dangerous for long-running Jenkins environments where multiple users interact with the same reports.
From an operational impact perspective, this vulnerability poses significant risks to Jenkins environments that utilize the FitNesse plugin for test reporting and documentation. Attackers who can control XML input files can execute arbitrary JavaScript code in the context of other users' browsers, potentially leading to session hijacking, credential theft, or further exploitation of the Jenkins instance. The vulnerability is particularly concerning because it requires minimal privileges to exploit - only the ability to influence XML input files, which may be accessible through various legitimate means such as test data submission, file uploads, or integration with other systems. This makes the attack surface broader than many other XSS vulnerabilities that require more privileged access or complex exploitation techniques.
The vulnerability aligns with CWE-79, which defines Cross-Site Scripting as a common weakness in web applications where untrusted data is improperly handled in web pages. It also maps to ATT&CK technique T1211, which covers the exploitation of vulnerabilities to execute malicious code in the context of the victim's browser. Organizations using Jenkins with the FitNesse plugin are particularly vulnerable if they do not maintain strict access controls over XML input files or if they allow untrusted users to contribute test data. The remediation strategy should focus on implementing proper input validation and output encoding practices within the plugin, ensuring that all user-controlled data is properly escaped before being rendered in the UI. Additionally, organizations should consider implementing Content Security Policy headers and regular security scanning of their Jenkins instances to detect and prevent such vulnerabilities from being exploited in production environments.
Mitigation efforts should include immediate patching of the FitNesse plugin to version 1.32 or later, which addresses the XSS vulnerability through proper input sanitization. Organizations should also implement network segmentation and access controls to limit who can submit XML content to Jenkins instances, particularly those with vulnerable plugins. Regular security assessments of Jenkins plugins and their configurations are essential to identify similar vulnerabilities in other components of the CI/CD pipeline. The vulnerability demonstrates the importance of proper input validation and output encoding in web applications, reinforcing the need for security-conscious development practices and comprehensive security testing throughout the software development lifecycle.