CVE-2020-2244 in Build Failure Analyzer Plugin
Summary
by MITRE
Jenkins Build Failure Analyzer Plugin 1.27.0 and earlier does not escape matching text in a form validation response, resulting in a cross-site scripting (XSS) vulnerability exploitable by attackers able to provide console output for builds used to test build log indications.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 11/12/2020
The Jenkins Build Failure Analyzer Plugin vulnerability represents a critical cross-site scripting flaw that emerged in versions 1.27.0 and earlier. This vulnerability resides within the plugin's handling of form validation responses where matching text is not properly escaped before being rendered in web interfaces. The flaw specifically affects the plugin's ability to process console output from builds, creating a pathway for malicious actors to inject harmful scripts into the application's user interface. The vulnerability's exploitation requires an attacker to have the ability to provide console output for builds used to test build log indications, which typically involves access to build execution environments or the ability to influence build processes.
The technical implementation of this vulnerability stems from improper input sanitization within the plugin's validation mechanisms. When the plugin processes build log data for analysis and validation, it fails to properly escape special characters in the matching text that appears in form validation responses. This omission creates an environment where malicious payloads can be executed within the context of a victim's browser session. The vulnerability manifests as a classic XSS attack vector, where crafted console output containing script tags or other malicious content can be processed by the plugin and subsequently rendered in the user interface without proper sanitization. The attack surface is particularly concerning because it leverages legitimate build process functionality to deliver malicious payloads.
The operational impact of this vulnerability extends beyond simple script execution, potentially enabling attackers to perform session hijacking, data theft, and privilege escalation within the Jenkins environment. An attacker who successfully exploits this vulnerability can execute arbitrary JavaScript code in the context of authenticated users, potentially gaining access to sensitive build information, credentials stored in the Jenkins environment, or even the ability to modify build configurations. The vulnerability's exploitation is particularly dangerous in enterprise environments where Jenkins is used for continuous integration and deployment processes, as it could compromise the integrity of the entire software delivery pipeline. The attack requires minimal privileges to exploit, making it a significant threat to organizations that rely on Jenkins for automated build processes.
Mitigation strategies for this vulnerability should focus on immediate patching of the affected plugin to version 1.28.0 or later, which contains the necessary input sanitization fixes. Organizations should also implement additional security measures including input validation at multiple layers, content security policy enforcement, and regular security assessments of Jenkins plugins. The vulnerability aligns with CWE-79, which describes cross-site scripting flaws in web applications, and maps to ATT&CK technique T1059.007 for scripting languages, specifically targeting the execution of malicious code through web interface vulnerabilities. Security teams should conduct comprehensive audits of all installed Jenkins plugins to identify similar vulnerabilities and ensure proper input sanitization practices are implemented throughout the application stack. Additionally, organizations should consider implementing web application firewalls and monitoring for suspicious console output patterns that might indicate attempted exploitation of this vulnerability.