CVE-2021-21641 in Promoted Builds Plugin
Summary
by MITRE • 04/07/2021
A cross-site request forgery (CSRF) vulnerability in Jenkins promoted builds Plugin 3.9 and earlier allows attackers to to promote builds.
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Analysis
by VulDB Data Team • 04/11/2021
The CVE-2021-21641 vulnerability represents a critical cross-site request forgery flaw within the Jenkins promoted builds plugin version 3.9 and earlier. This vulnerability exposes Jenkins environments to unauthorized build promotion activities that can be executed without proper user consent or authentication. The promoted builds plugin is commonly used in continuous integration and deployment pipelines to manage build promotion workflows between different environments such as development, testing, and production stages. When exploited, this CSRF vulnerability allows attackers to manipulate the build promotion process through malicious web requests that appear to originate from authenticated users.
The technical implementation of this vulnerability stems from insufficient validation of request origins and lack of proper anti-CSRF token mechanisms within the plugin's web endpoints. Attackers can craft malicious HTML pages or leverage existing web applications to submit requests that trigger build promotion actions on behalf of authenticated users. The vulnerability specifically affects the plugin's ability to verify that requests are genuinely initiated by the legitimate user rather than being submitted through crafted attack vectors. This flaw operates at the application layer where HTTP requests are processed without adequate origin verification or token-based authentication mechanisms. The absence of proper CSRF protection tokens means that legitimate users who are authenticated to Jenkins can be tricked into executing unintended build promotion actions through social engineering or compromised web pages.
The operational impact of this vulnerability extends beyond simple unauthorized access to encompass potential disruption of continuous integration pipelines and compromise of software deployment processes. Attackers could promote malicious builds to production environments, potentially introducing security vulnerabilities or backdoors into deployed applications. The implications are particularly severe in environments where build promotion decisions directly control deployment to critical systems or customer-facing applications. Jenkins administrators may face unauthorized changes to build workflows, corrupted deployment pipelines, and potential compromise of the entire CI/CD infrastructure. This vulnerability can also facilitate further attacks by enabling attackers to manipulate build artifacts or trigger automated deployment processes that could lead to system compromise or data exposure.
Organizations should immediately upgrade to Jenkins promoted builds plugin version 3.10 or later to remediate this vulnerability. The fix implements proper CSRF token validation and origin checking mechanisms that prevent unauthorized build promotion requests from succeeding. Security teams should also review their Jenkins configurations to ensure proper access controls and monitoring of build promotion activities. The vulnerability aligns with CWE-352, which specifically addresses cross-site request forgery weaknesses in web applications, and maps to ATT&CK technique T1078.004 for valid accounts and T1059.001 for command and scripting interpreter. Organizations should implement additional security controls including web application firewalls, network segmentation, and regular security assessments of their Jenkins environments to prevent exploitation of similar vulnerabilities. Regular patch management procedures should be enforced to ensure all Jenkins plugins remain up to date with security fixes and to maintain overall system integrity.