CVE-2016-3727 in Jenkins
Summary
by MITRE
The API URL computer/(master)/api/xml in CloudBees Jenkins before 2.3 and LTS before 1.651.2 allows remote authenticated users with extended read permission for the master node to obtain sensitive information about the global configuration via unspecified vectors.
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Analysis
by VulDB Data Team • 08/19/2022
The vulnerability identified as CVE-2016-3727 represents a critical information disclosure flaw within CloudBees Jenkins versions prior to 2.3 and LTS versions before 1.651.2. This security weakness specifically affects the API URL endpoint computer/(master)/api/xml which is designed to provide system information through an XML-based interface. The vulnerability arises from insufficient access controls and improper authorization checks within the Jenkins API implementation, allowing authenticated users with extended read permissions for the master node to extract sensitive global configuration data that should remain restricted to administrators.
The technical flaw stems from the improper handling of API access permissions within Jenkins' master node configuration system. When authenticated users access the specified API endpoint, the system fails to adequately validate whether the requesting user possesses the appropriate administrative privileges required to view global configuration details. This represents a violation of the principle of least privilege and demonstrates a classic authorization bypass vulnerability. The unspecified vectors mentioned in the description suggest that the flaw exists in how the system processes and validates access tokens or session information when processing API requests for master node configuration data.
The operational impact of this vulnerability extends beyond simple information disclosure, as the compromised global configuration data may include sensitive system parameters, credential storage locations, plugin configurations, and other administrative details that could be leveraged by attackers to escalate privileges or conduct further exploitation. This vulnerability directly violates the security principle of separation of duties, as it allows users with relatively low-level permissions to access data typically restricted to system administrators. The exposure of global configuration information creates potential attack vectors for advanced persistent threats and can facilitate more sophisticated attacks against the Jenkins infrastructure.
Organizations utilizing affected Jenkins versions should immediately implement mitigations including upgrading to patched versions 2.3 and LTS 1.651.2, which contain the necessary access control improvements. Additional protective measures include implementing network segmentation to limit access to Jenkins API endpoints, enforcing stricter authentication controls, and monitoring API access logs for suspicious activities. This vulnerability aligns with CWE-284, which addresses improper access control, and maps to ATT&CK technique T1078 for valid accounts and T1566 for credential access, as it enables unauthorized information gathering through legitimate administrative interfaces. Security teams should conduct comprehensive audits of Jenkins configurations and review all user permissions to ensure proper segregation of duties and prevent similar authorization bypass scenarios.