CVE-2017-2652 in Distributed Fork Plugin
Summary
by MITRE
It was found that there were no permission checks performed in the Distributed Fork plugin before and including 1.5.0 for Jenkins that provides the dist-fork CLI command beyond the basic check for Overall/Read permission, allowing anyone with that permission to run arbitrary shell commands on all connected nodes.
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Analysis
by VulDB Data Team • 03/10/2020
The vulnerability identified as CVE-2017-2652 represents a critical authorization flaw within the Distributed Fork plugin for Jenkins, specifically affecting versions through 1.5.0. This issue stems from insufficient permission validation mechanisms that fail to properly enforce access controls for the dist-fork command functionality. The flaw exists at the core of Jenkins' security model where the plugin does not implement additional authorization checks beyond the basic Overall/Read permission level, creating a significant escalation path for attackers who already possess minimal read access to the system.
The technical implementation of this vulnerability allows any user with Overall/Read permission to execute arbitrary shell commands across all connected Jenkins nodes. This represents a fundamental breakdown in the principle of least privilege and demonstrates a clear violation of security separation controls. The distributed nature of Jenkins means that compromising a single node with this vulnerability can potentially lead to compromise of the entire build infrastructure, as the affected plugin operates across all connected agents and master systems. The flaw essentially transforms read-only access into full system command execution capability, bypassing normal security boundaries that should prevent unauthorized code execution.
From an operational impact perspective, this vulnerability creates a severe risk for organizations relying on Jenkins for continuous integration and deployment processes. Attackers can leverage this flaw to execute malicious commands, potentially leading to data exfiltration, system compromise, or disruption of build processes. The vulnerability affects the integrity and confidentiality of the entire Jenkins environment, as it allows unauthorized users to gain control over build agents and potentially access sensitive source code repositories, build artifacts, and deployment configurations. This risk is particularly elevated in environments where Jenkins is used for production deployments or contains access to privileged systems.
The vulnerability aligns with CWE-284, which addresses improper access control issues, and maps to ATT&CK technique T1059, specifically command and scripting interpreter, as it enables adversaries to execute arbitrary commands on target systems. Organizations should immediately upgrade to versions of the Distributed Fork plugin that address this authorization flaw, implement additional monitoring for unauthorized command execution, and review their overall Jenkins security configuration. Network segmentation and additional access controls beyond the basic Jenkins permissions should be enforced to limit the blast radius of such vulnerabilities. The incident underscores the importance of thorough security testing for plugins and the necessity of maintaining up-to-date software versions to prevent exploitation of known authorization flaws that can lead to complete system compromise.