CVE-2016-4986 in TAP Plugin
Summary
by MITRE
Directory traversal vulnerability in the TAP plugin before 1.25 in Jenkins allows remote attackers to read arbitrary files via an unspecified parameter.
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Analysis
by VulDB Data Team • 11/12/2022
The CVE-2016-4986 vulnerability represents a critical directory traversal flaw within the TAP plugin for Jenkins, specifically affecting versions prior to 1.25. This vulnerability resides in the plugin's handling of user-supplied input parameters, creating an exploitable condition that allows remote attackers to access arbitrary files on the underlying system. The TAP plugin, designed for test result processing and reporting, fails to properly sanitize input parameters that control file access operations, enabling attackers to manipulate file paths through crafted requests. This issue directly impacts the security posture of Jenkins installations that utilize the affected plugin, potentially exposing sensitive configuration files, source code, credentials, and other confidential data stored on the server.
The technical implementation of this vulnerability stems from inadequate input validation and sanitization within the plugin's file access routines. When the TAP plugin processes test result files or related parameters, it fails to properly validate or filter user-provided input that influences file system operations. Attackers can exploit this by crafting malicious requests containing directory traversal sequences such as ../ or ..\ that bypass normal file access controls. The vulnerability operates at the application layer, specifically targeting the plugin's file handling mechanisms rather than the core Jenkins platform, making it particularly insidious as it can be leveraged to access files outside of the intended plugin scope. This flaw aligns with CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks.
The operational impact of CVE-2016-4986 extends beyond simple information disclosure, potentially enabling attackers to access critical system resources and sensitive data. An attacker who successfully exploits this vulnerability could retrieve configuration files containing database credentials, API keys, or other authentication tokens that might lead to further system compromise. The vulnerability also poses risks to intellectual property as source code repositories, build artifacts, and test data could be accessed without authorization. Given that Jenkins servers often run with elevated privileges and may contain access to development environments, this vulnerability can serve as a stepping stone for more extensive attacks. The remote nature of the exploit means that attackers do not require local system access or physical presence, making the vulnerability particularly dangerous in multi-tenant environments or public-facing Jenkins installations.
Organizations should implement immediate mitigation strategies to address this vulnerability, beginning with upgrading the TAP plugin to version 1.25 or later where the issue has been resolved. The plugin upgrade process should be conducted carefully to ensure compatibility with existing Jenkins configurations and test result processing workflows. Additional defensive measures include implementing network segmentation to limit access to Jenkins servers, configuring proper access controls and authentication mechanisms, and monitoring for suspicious file access patterns. Security teams should also consider implementing web application firewalls that can detect and block directory traversal attempts, as well as conducting regular vulnerability assessments to identify other potentially affected plugins or components within the Jenkins ecosystem. The remediation approach should align with ATT&CK framework's T1078 credential access techniques, ensuring that defensive measures address both the immediate vulnerability and broader access control considerations. Organizations must also review their overall Jenkins security posture, as this vulnerability highlights potential gaps in input validation and privilege management that could affect other components within the system.