CVE-2020-2264 in Custom Job Icon Plugin
Summary
by MITRE
Jenkins Custom Job Icon Plugin 0.2 and earlier does not escape the job descriptions in tooltips, resulting in a stored cross-site scripting (XSS) vulnerability exploitable by attackers with Job/Configure permission.
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Analysis
by VulDB Data Team • 09/16/2020
The Jenkins Custom Job Icon Plugin vulnerability identified as CVE-2020-2264 represents a critical stored cross-site scripting flaw that emerged from inadequate input sanitization within the plugin's tooltip functionality. This vulnerability affects versions 0.2 and earlier of the Custom Job Icon Plugin, which is widely used within Jenkins environments to enhance job visualization through custom icons. The flaw specifically manifests when job descriptions are rendered within tooltips without proper HTML escaping, creating an avenue for malicious actors to inject persistent JavaScript code into the Jenkins interface.
The technical implementation of this vulnerability stems from the plugin's failure to properly sanitize user-controllable input when generating tooltip content. When administrators or users configure job descriptions within Jenkins, the system stores these descriptions in a manner that does not adequately escape special characters that could be interpreted as HTML or JavaScript markup. This allows an attacker with the Job/Configure permission level to craft malicious job descriptions containing embedded script tags or other XSS payloads that persist within the system. The vulnerability is classified as stored XSS because the malicious code is saved server-side and executed whenever the tooltip is rendered, making it particularly dangerous as it affects all users who encounter the affected job descriptions.
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 can configure jobs can potentially steal session cookies, redirect users to malicious sites, or execute arbitrary commands on the Jenkins server depending on the underlying system configuration and permissions. The vulnerability directly violates security principles outlined in CWE-79, which addresses cross-site scripting vulnerabilities, and aligns with ATT&CK technique T1059.007 for command and scripting interpreter. The attack surface is particularly concerning given that Jenkins is often used in continuous integration and deployment pipelines where it may have elevated privileges and access to sensitive build artifacts and credentials.
Mitigation strategies for CVE-2020-2264 require immediate action to upgrade the Custom Job Icon Plugin to version 0.3 or later, which includes proper input sanitization and HTML escaping mechanisms. Organizations should also implement strict access controls to limit who can configure jobs within Jenkins, as the vulnerability requires the Job/Configure permission to exploit. Additional protective measures include enabling Jenkins security features such as CSRF protection, implementing proper input validation at multiple layers, and conducting regular security audits of installed plugins. The vulnerability demonstrates the importance of input sanitization in web applications and highlights how seemingly minor functionality flaws can create significant security risks in enterprise environments where Jenkins serves as a central automation hub.