CVE-2023-43499 in Build Failure Analyzer Plugin
Summary
by MITRE • 09/20/2023
Jenkins Build Failure Analyzer Plugin 2.4.1 and earlier does not escape Failure Cause names in build logs, resulting in a stored cross-site scripting (XSS) vulnerability exploitable by attackers able to create or update Failure Causes.
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Analysis
by VulDB Data Team • 10/13/2023
The Jenkins Build Failure Analyzer Plugin vulnerability represents a critical security flaw that undermines the integrity of continuous integration and delivery environments. This vulnerability exists in versions 2.4.1 and earlier of the plugin, which is widely used for analyzing and categorizing build failures within Jenkins environments. The flaw stems from inadequate input sanitization mechanisms that fail to properly escape Failure Cause names when these are rendered in build logs, creating a persistent vector for malicious code execution.
The technical implementation of this vulnerability manifests through improper output encoding practices within the plugin's logging mechanism. When administrators or developers create or update Failure Causes within the build process, the plugin stores these identifiers without sufficient HTML escaping or sanitization. This omission allows attackers who can manipulate the Failure Cause data to inject malicious scripts that execute in the context of other users who view the build logs. The stored nature of this vulnerability means that malicious payloads persist even after the initial injection point, making the attack surface particularly dangerous for long-running Jenkins installations.
The operational impact of this vulnerability extends beyond simple script execution, as it provides attackers with a foothold for more sophisticated attacks within the Jenkins environment. An attacker who successfully exploits this XSS vulnerability could potentially access sensitive build information, manipulate build results, or even escalate privileges within the Jenkins instance. The vulnerability is particularly concerning because it requires minimal privileges to exploit - attackers only need the ability to create or update Failure Causes, which are often accessible to developers or CI/CD pipeline administrators. This accessibility significantly broadens the potential attack surface, as many Jenkins installations have multiple users with varying levels of access to build failure management features.
From a cybersecurity perspective, this vulnerability maps directly to CWE-79 which describes Cross-Site Scripting flaws, and aligns with ATT&CK technique T1211 for lateral movement through compromised build systems. The vulnerability also demonstrates poor input validation practices that violate security best practices for web application development. Organizations utilizing Jenkins with the affected plugin are at risk of data exfiltration, build manipulation, and potential compromise of the entire CI/CD pipeline. The stored nature of the XSS payload means that even users who do not have direct access to the plugin's configuration may be vulnerable when they view build logs containing malicious content.
Mitigation strategies should focus on immediate plugin version updates to 2.4.2 or later, which contain the necessary escaping mechanisms. Administrators should also implement additional security controls such as restricting permissions for Failure Cause management, implementing content security policies, and regularly auditing build log contents for suspicious entries. Organizations should conduct comprehensive vulnerability assessments of their Jenkins environments to identify other potentially affected plugins and ensure proper input sanitization across all web-facing components. The vulnerability highlights the importance of proper security testing in CI/CD environments and the critical need for input validation in all user-facing application components, particularly those that render user-provided data in web contexts.