CVE-2017-1000089 in Jenkins
Summary
by MITRE
Builds in Jenkins are associated with an authentication that controls the permissions that the build has to interact with other elements in Jenkins. The Pipeline: Build Step Plugin did not check the build authentication it was running as and allowed triggering any other project in Jenkins.
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Analysis
by VulDB Data Team • 11/22/2019
The vulnerability identified as CVE-2017-1000089 affects Jenkins continuous integration and delivery platform through the Pipeline Build Step Plugin, representing a critical authorization bypass flaw that undermines the fundamental security model of the system. This vulnerability exists within the plugin's implementation where it fails to properly validate the authentication context of the build process, creating a pathway for unauthorized privilege escalation. The issue stems from the plugin's failure to enforce the security boundaries that normally govern how builds interact with other Jenkins projects, effectively allowing any authenticated user to trigger arbitrary projects regardless of their actual permissions or access rights within the system.
The technical flaw manifests in the plugin's improper handling of authentication contexts during pipeline execution, where it relies on the credentials of the initiating build rather than validating whether those credentials should permit the specific action being attempted. This represents a classic authorization flaw that aligns with CWE-285, which addresses improper authorization in software systems. The vulnerability specifically enables what is known as privilege escalation through unauthorized access to build triggers, allowing attackers to execute builds against projects they should not normally be able to access or modify. The flaw occurs because the plugin does not perform proper permission checks before executing the build step, essentially bypassing Jenkins' built-in security mechanisms that are designed to maintain project isolation and access control.
The operational impact of this vulnerability is severe and far-reaching within Jenkins environments, particularly in organizations that rely on the platform for automated builds and deployments. An attacker with access to trigger builds could potentially execute malicious code against projects with higher privileges, access sensitive build artifacts, or trigger builds that could compromise other systems within the organization's infrastructure. This vulnerability particularly affects environments where Jenkins is used for continuous delivery pipelines, as it allows for unauthorized access to build processes that may have elevated permissions or access to production systems. The attack vector is relatively straightforward since it only requires the ability to trigger builds, which is often granted to developers or CI/CD pipeline users, making the exploit accessible to a broad range of potential threat actors.
Organizations should implement immediate mitigations including updating to the patched version of the Pipeline Build Step Plugin, reviewing and tightening Jenkins security configurations, and implementing additional access controls such as role-based access control enforcement. The vulnerability demonstrates the critical importance of proper authentication and authorization checking in security-sensitive components, particularly those that handle cross-project operations. Organizations should also consider implementing monitoring and alerting for unauthorized build triggers and review their Jenkins security policies to ensure that the principle of least privilege is properly enforced across all pipeline components. This vulnerability highlights the need for comprehensive security testing of plugins and integration points within CI/CD systems, as these components often serve as attack vectors for privilege escalation and unauthorized access to critical infrastructure elements. The flaw also aligns with ATT&CK technique T1078 which covers valid accounts and privilege escalation, as it allows attackers to leverage legitimate build triggers to gain access to unauthorized resources through the existing authentication mechanisms.