CVE-2020-2176 in useMango Runner Plugin
Summary
by MITRE
Multiple form validation endpoints in Jenkins useMango Runner Plugin 1.4 and earlier do not escape values received from the useMango service, resulting in a cross-site scripting (XSS) vulnerability exploitable by users able to control the values returned from the useMango service.
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Analysis
by VulDB Data Team • 04/08/2020
The vulnerability identified as CVE-2020-2176 affects the useMango Runner Plugin for Jenkins versions 1.4 and earlier, representing a critical cross-site scripting flaw that undermines web application security. This vulnerability resides within multiple form validation endpoints that process data returned from the useMango service, creating an exploitable pathway for malicious actors to inject harmful scripts into the Jenkins web interface. The issue stems from inadequate input sanitization and output escaping mechanisms within the plugin's validation routines, which fail to properly handle potentially malicious data received from external services.
The technical flaw manifests when the plugin receives values from the useMango service and subsequently incorporates these values into web responses without appropriate HTML escaping or sanitization. This creates an environment where attackers can manipulate the data flow to inject malicious JavaScript code that executes within the context of other users' browsers. The vulnerability is particularly dangerous because it requires minimal privileges to exploit, as users who can influence the values returned from the useMango service can directly manipulate the plugin's behavior. This aligns with CWE-79, which describes cross-site scripting vulnerabilities resulting from improper output escaping in web applications.
The operational impact of this vulnerability extends beyond simple script injection, as it can enable attackers to perform session hijacking, steal sensitive credentials, manipulate data within the Jenkins environment, or redirect users to malicious websites. Since Jenkins serves as a central automation server for many organizations, exploitation of this vulnerability can compromise entire CI/CD pipelines and provide attackers with elevated privileges to access build artifacts, source code repositories, and configuration data. The vulnerability affects the integrity and confidentiality of the Jenkins environment, potentially leading to supply chain compromises when automated builds are involved.
Security practitioners should immediately upgrade to Jenkins plugin versions that address this vulnerability, as the useMango Runner Plugin versions 1.5 and later include proper input sanitization and output escaping mechanisms. Organizations should also implement network-level controls to monitor and restrict communication with the useMango service, while applying principle of least privilege to limit which users can influence the service responses. The vulnerability demonstrates the importance of proper input validation and output escaping as outlined in the OWASP Top Ten and ATT&CK framework's T1203 technique for exploitation of web application vulnerabilities. Additionally, implementing Content Security Policy headers and regular security scanning of Jenkins plugins can help detect and prevent similar issues in other components of the automation infrastructure.