CVE-2016-4987 in Image Gallery Plugin
Summary
by MITRE
Directory traversal vulnerability in the Image Gallery plugin before 1.4 in Jenkins allows remote attackers to list arbitrary directories and read arbitrary files via unspecified form fields.
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Analysis
by VulDB Data Team • 11/12/2022
The CVE-2016-4987 vulnerability represents a critical directory traversal flaw within the Image Gallery plugin for Jenkins, specifically affecting versions prior to 1.4. This vulnerability falls under the CWE-22 category, which defines improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks. The flaw enables remote attackers to exploit insecure input handling within the plugin's file operations, allowing them to bypass normal access controls and gain unauthorized access to sensitive system resources. The vulnerability manifests through unspecified form fields that are processed without proper validation or sanitization, creating an attack surface where malicious input can manipulate file system operations.
The technical implementation of this vulnerability exploits the lack of input validation in the Image Gallery plugin's handling of user-supplied parameters. Attackers can construct malicious requests that include directory traversal sequences such as "../" or "..\\" to navigate outside the intended directory boundaries. When the plugin processes these requests, it fails to properly sanitize the input before using it in file system operations, resulting in the exposure of arbitrary directories and files on the server. This type of vulnerability represents a fundamental failure in secure coding practices and demonstrates poor input validation mechanisms that should be implemented at multiple layers of the application architecture. The attack vector operates entirely through the web interface, making it particularly dangerous as it requires no local system access or elevated privileges.
The operational impact of CVE-2016-4987 extends beyond simple information disclosure, as it can potentially lead to complete system compromise. An attacker who successfully exploits this vulnerability can enumerate the file system structure, read sensitive configuration files, access source code repositories, and potentially discover credentials stored in configuration files. The exposure of arbitrary directories may reveal not only plugin-specific files but also system files, user data, and potentially other applications running on the same server. This vulnerability directly impacts the principle of least privilege and can undermine the security posture of Jenkins installations, particularly in environments where the plugin is used to manage image galleries for web applications or documentation systems. The vulnerability's remote exploitability means that attackers can leverage it from outside the network perimeter without requiring physical access or prior authentication to the system.
Mitigation strategies for CVE-2016-4987 should focus on immediate patching of the Image Gallery plugin to version 1.4 or later, where the directory traversal vulnerability has been addressed through proper input validation and sanitization. Organizations should implement comprehensive input validation mechanisms that filter or reject suspicious characters and sequences before processing user input in file operations. The principle of defense in depth should be applied by restricting file system access permissions for the Jenkins service account and implementing web application firewalls that can detect and block directory traversal patterns. Additionally, regular security assessments should be conducted to identify and remediate similar vulnerabilities in other plugins and applications. This vulnerability aligns with ATT&CK technique T1083 (File and Directory Discovery) and T1566 (Phishing), as it enables attackers to discover system files and potentially gather intelligence for further attacks. Organizations should also consider implementing network segmentation and monitoring solutions to detect anomalous file system access patterns that may indicate exploitation attempts. The vulnerability underscores the importance of maintaining up-to-date software components and following secure coding practices that prevent path traversal attacks through proper input validation and access control mechanisms.