CVE-2020-2317 in FindBugs Plugin
Summary
by MITRE • 11/04/2020
Jenkins FindBugs Plugin 5.0.0 and earlier does not escape the annotation message in tooltips, resulting in a stored cross-site scripting (XSS) vulnerability exploitable by attackers able to provide report files to Jenkins FindBugs Plugin's post build step.
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Analysis
by VulDB Data Team • 12/02/2020
The Jenkins FindBugs Plugin vulnerability identified as CVE-2020-2317 represents a critical stored cross-site scripting flaw that emerged in versions 5.0.0 and earlier of the popular Jenkins plugin. This vulnerability stems from inadequate input sanitization within the plugin's handling of annotation messages that are displayed in tooltips. The flaw occurs during the post-build step processing where the plugin receives and processes report files containing FindBugs analysis results, creating a persistent security risk that can be exploited by malicious actors who gain the ability to upload or modify report files within the Jenkins environment.
The technical implementation of this vulnerability resides in the plugin's failure to properly escape or sanitize user-controllable data before rendering it in web tooltips. When FindBugs analysis reports contain malicious script content within annotation messages, the plugin directly incorporates this unescaped data into HTML tooltips without proper sanitization. This stored XSS vulnerability allows attackers to inject malicious JavaScript code that executes in the context of other users' browsers when they view the tooltips containing the malicious content. The vulnerability is particularly dangerous because it leverages the legitimate post-build step functionality of Jenkins, making it difficult to distinguish between benign and malicious report files.
The operational impact of CVE-2020-2317 extends beyond simple script execution, as it can enable attackers to perform various malicious activities including session hijacking, data exfiltration, and privilege escalation within the Jenkins environment. An attacker who can upload or modify report files through legitimate means or by compromising a build server can craft malicious FindBugs reports containing XSS payloads that persist in the system. This creates a long-term threat vector where the malicious code executes every time users interact with the tooltips, potentially allowing attackers to steal credentials, access sensitive build information, or compromise the entire Jenkins infrastructure. The vulnerability affects organizations that rely on FindBugs plugin for code quality analysis and security monitoring.
This vulnerability aligns with CWE-79 which specifically addresses cross-site scripting flaws, and maps to ATT&CK technique T1059.007 for script injection. Organizations should immediately upgrade to Jenkins FindBugs Plugin version 5.0.1 or later, which implements proper input sanitization and output escaping for tooltip content. Additional mitigations include implementing strict file upload controls, restricting write permissions to Jenkins build directories, and employing web application firewalls to detect and block suspicious script content. Security teams should also conduct thorough audits of Jenkins plugin configurations and review access controls to limit the ability of unauthorized users to upload or modify report files, as the vulnerability requires an attacker to have some level of access to the Jenkins build process to exploit effectively.