CVE-2017-1000087 in Jenkins
Summary
by MITRE
GitHub Branch Source provides a list of applicable credential IDs to allow users configuring a job to select the one they'd like to use. This functionality did not check permissions, allowing any user with Overall/Read permission to get a list of valid credentials IDs. Those could be used as part of an attack to capture the credentials using another vulnerability.
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Analysis
by VulDB Data Team • 11/22/2019
The vulnerability identified as CVE-2017-1000087 resides within the GitHub Branch Source plugin for Jenkins, a widely used continuous integration and delivery platform. This issue represents a critical authorization flaw that undermines the security model of the system by exposing sensitive credential information to unauthorized users. The vulnerability specifically affects the plugin's credential management functionality, where it fails to properly enforce access controls when presenting credential selection options to users configuring jobs. This misconfiguration creates a pathway for privilege escalation and credential theft attacks that can have far-reaching consequences for organizations relying on Jenkins for their automation workflows.
The technical flaw manifests in the plugin's failure to implement proper permission checks when retrieving and displaying credential IDs to users. When administrators configure jobs that require authentication to access external repositories, the system should only present credentials that the currently authenticated user has authorization to use. However, the vulnerability allows any user with merely Overall/Read permission to enumerate all valid credential IDs within the system. This enumeration capability bypasses the intended access controls and creates a reconnaissance opportunity for malicious actors. The exposed credential IDs can then be leveraged in conjunction with other vulnerabilities to capture actual credential values, making this a particularly dangerous flaw in the context of Jenkins security architecture.
The operational impact of this vulnerability extends beyond simple information disclosure, as it enables attackers to systematically gather credential information that can be used to compromise the entire automation infrastructure. An attacker with Overall/Read permission can discover which credentials are available and then potentially exploit other vulnerabilities to extract the actual credential values, leading to unauthorized access to source code repositories, deployment systems, and other sensitive resources. This vulnerability particularly affects organizations that rely on Jenkins for CI/CD pipelines, as it provides attackers with the means to escalate privileges and gain access to systems that should be protected by proper authentication controls. The flaw essentially undermines the principle of least privilege that is fundamental to secure system design.
Security mitigations for this vulnerability should focus on implementing proper authorization checks within the GitHub Branch Source plugin to ensure that credential ID enumeration only occurs for users with appropriate permissions. Organizations should immediately update to patched versions of the plugin where available, as this vulnerability has been addressed in subsequent releases. Additionally, implementing network segmentation and access controls to limit which users can access Jenkins systems can help reduce the attack surface. The vulnerability aligns with CWE-284, which describes improper access control, and represents a clear violation of the principle of least privilege as outlined in the MITRE ATT&CK framework for credential access techniques. Regular security audits of Jenkins plugins and their permission models should be conducted to identify similar authorization flaws that could enable credential enumeration attacks. Organizations should also implement monitoring for unusual credential enumeration patterns and establish proper incident response procedures to address potential exploitation of such vulnerabilities.