CVE-2018-1000068 in Jenkins
Summary
by MITRE
An improper input validation vulnerability exists in Jenkins versions 2.106 and earlier, and LTS 2.89.3 and earlier, that allows an attacker to access plugin resource files in the META-INF and WEB-INF directories that should not be accessible, if the Jenkins home directory is on a case-insensitive file system.
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Analysis
by VulDB Data Team • 02/04/2021
This vulnerability resides in Jenkins continuous integration and delivery platform where improper input validation creates a path traversal risk affecting versions up to 2.106 and LTS up to 2.89.3. The flaw specifically manifests when Jenkins operates on file systems that do not distinguish between uppercase and lowercase file names, creating a condition where attackers can bypass normal access controls to reach sensitive plugin resource files. The vulnerability is categorized under CWE-22 Path Traversal and aligns with ATT&CK technique T1059.007 Command and Scripting Interpreter for privilege escalation through resource manipulation.
The technical implementation exploits case-insensitive file system behavior by constructing malicious URLs that reference plugin resources using different case variations than their actual file names. When Jenkins processes these requests, it fails to properly validate input paths, allowing access to META-INF and WEB-INF directories that contain sensitive configuration files, class files, and other resources typically restricted from external access. This occurs because the application does not normalize or sanitize file paths before processing, enabling attackers to craft requests that traverse the intended directory structure.
Operational impact of this vulnerability extends beyond simple information disclosure, as access to WEB-INF directories can potentially expose application configuration files, database connection details, and other sensitive metadata that could aid in further exploitation. Attackers could leverage this access to gather intelligence about the Jenkins environment, potentially leading to privilege escalation or lateral movement within the network infrastructure. The vulnerability is particularly concerning in enterprise environments where Jenkins serves as a central automation platform managing critical build and deployment processes.
Mitigation strategies should focus on immediate patching of affected Jenkins versions to the latest stable releases where this vulnerability has been resolved. Organizations should also implement network segmentation and access controls to limit exposure of Jenkins instances to untrusted networks. Additional defensive measures include enabling Jenkins security features such as CSRF protection, implementing proper file system permissions, and conducting regular security audits of plugin installations. The vulnerability demonstrates the importance of proper input validation and path sanitization in web applications, particularly when operating in environments with case-insensitive file systems. Organizations should also consider implementing automated vulnerability scanning tools to identify similar issues in other applications and dependencies within their infrastructure.