CVE-2017-2611 in Jenkins
Summary
by MITRE
Jenkins before versions 2.44, 2.32.2 is vulnerable to an insufficient permission check for periodic processes (SECURITY-389). The URLs /workspaceCleanup and /fingerprintCleanup did not perform permission checks, allowing users with read access to Jenkins to trigger these background processes (that are otherwise performed daily), possibly causing additional load on Jenkins master and agents.
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Analysis
by VulDB Data Team • 03/08/2023
This vulnerability exists in Jenkins versions prior to 2.44 and 2.32.2 where insufficient permission checks were implemented for specific background processes. The flaw specifically affects the /workspaceCleanup and /fingerprintCleanup endpoints which are designed to perform routine maintenance operations on the Jenkins master and its agents. These URLs lack proper authentication and authorization verification, creating a critical security gap that allows unauthorized users to trigger resource-intensive background tasks. The vulnerability is categorized under CWE-284 which addresses improper access control, specifically the lack of permission validation for privileged operations. This issue falls within the ATT&CK framework under privilege escalation and defense evasion techniques, as it enables attackers to consume excessive system resources without proper authorization.
The technical implementation of this vulnerability stems from the absence of proper permission validation mechanisms in the Jenkins web application framework. When users with read-only access attempt to access the /workspaceCleanup and /fingerprintCleanup endpoints, the system fails to verify whether the requesting user possesses the necessary administrative privileges to execute these operations. This oversight allows malicious actors or compromised accounts with minimal permissions to initiate background processes that typically run automatically on a scheduled basis. The affected endpoints are designed to perform cleanup operations on workspace directories and fingerprint files respectively, which can be computationally intensive and resource-consuming tasks that impact system performance.
The operational impact of this vulnerability extends beyond simple resource consumption, as it can lead to significant performance degradation and potential denial of service conditions. Attackers can repeatedly trigger these cleanup processes, causing excessive load on both the Jenkins master server and its connected agents, potentially leading to system instability or complete service unavailability. The resource exhaustion can manifest in increased CPU utilization, memory consumption, and disk I/O operations that may affect legitimate build processes and user activities. This vulnerability particularly affects organizations that rely heavily on Jenkins for continuous integration and deployment workflows, where system performance and availability are critical factors for business operations.
Organizations should immediately upgrade to Jenkins versions 2.44 or 2.32.2 to address this vulnerability, as these releases include proper permission checks for the affected endpoints. System administrators should also implement additional monitoring and alerting mechanisms to detect unusual patterns of cleanup process execution, which could indicate exploitation attempts. The mitigation strategy should include reviewing and restricting access permissions for Jenkins endpoints, particularly those that perform administrative operations. Security teams should consider implementing network-level controls to restrict access to these specific URLs and establish baseline performance metrics to quickly identify when resource consumption exceeds normal operational parameters. Additionally, regular security assessments and penetration testing should be conducted to identify similar permission-related vulnerabilities in other Jenkins plugins and components.