CVE-2017-2602 in Jenkins
Summary
by MITRE
jenkins before versions 2.44, 2.32.2 is vulnerable to an improper blacklisting of the Pipeline metadata files in the agent-to-master security subsystem. This could allow metadata files to be written to by malicious agents (SECURITY-358).
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Analysis
by VulDB Data Team • 03/13/2023
The vulnerability identified as CVE-2017-2602 affects Jenkins continuous integration and delivery platform versions prior to 2.44 and 2.32.2, representing a critical security flaw in the agent-to-master security subsystem. This issue stems from an improper blacklisting mechanism that fails to adequately restrict write access to Pipeline metadata files, creating a significant attack vector for malicious actors. The vulnerability specifically targets the security controls designed to prevent unauthorized modification of pipeline execution metadata, which serves as a fundamental component of Jenkins' security architecture for distributed builds.
The technical flaw manifests in the agent-to-master security subsystem where Jenkins implements a blacklist mechanism to prevent malicious agents from writing to sensitive files. However, the implementation contains a critical oversight in the blacklisting process for Pipeline metadata files, allowing malicious agents to bypass these security restrictions and write to files that should remain protected. This improper blacklisting creates a privilege escalation scenario where unauthorized agents can manipulate pipeline execution metadata, potentially leading to arbitrary code execution or complete system compromise. The vulnerability directly relates to CWE-284 which addresses improper access control, specifically in the context of file system permissions and security subsystems.
The operational impact of this vulnerability extends beyond simple unauthorized file modifications, as it enables malicious actors to manipulate pipeline execution flows and potentially gain deeper system access. Attackers could exploit this weakness to inject malicious metadata that would be executed during pipeline processing, creating a persistent backdoor or enabling more sophisticated attacks. The security implications are particularly severe because Jenkins pipelines often contain sensitive build information, deployment configurations, and access credentials that could be compromised through this attack vector. This vulnerability affects organizations that rely on Jenkins for automated CI/CD processes, potentially exposing their entire software supply chain to compromise.
Organizations should immediately implement mitigations including upgrading to Jenkins versions 2.44 or 2.32.2 where the vulnerability has been patched, and conducting thorough security assessments of existing pipeline configurations. The patch addresses the improper blacklisting by correctly implementing file access controls for Pipeline metadata files, ensuring that only authorized agents can write to these critical system components. Additional mitigations include implementing network segmentation between Jenkins agents and master nodes, monitoring for unauthorized file modifications, and conducting regular security audits of pipeline configurations. From an ATT&CK framework perspective, this vulnerability maps to privilege escalation techniques and persistence mechanisms, as attackers could use the compromised metadata files to establish long-term access to CI/CD environments. Organizations should also review their agent management policies and implement additional security controls such as code signing verification and enhanced monitoring of pipeline execution artifacts to prevent exploitation of similar vulnerabilities in the future.