CVE-2020-10086 in Community Edition
Summary
by MITRE
GitLab 10.4 through 12.8.1 allows Directory Traversal. A particular endpoint was vulnerable to a directory traversal vulnerability, leading to arbitrary file read.
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Analysis
by VulDB Data Team • 03/14/2020
The vulnerability identified as CVE-2020-10086 represents a critical directory traversal flaw within GitLab versions ranging from 10.4 through 12.8.1, exposing organizations to significant security risks. This vulnerability resides in a specific endpoint that processes user input without proper validation, creating an opportunity for malicious actors to exploit the system's file handling mechanisms. The flaw enables unauthorized access to arbitrary files on the server by manipulating input parameters to traverse directory structures beyond intended boundaries. Such a vulnerability directly impacts GitLab's file system access controls and can potentially expose sensitive configuration files, source code repositories, and other critical system data.
The technical implementation of this directory traversal vulnerability stems from inadequate input sanitization within GitLab's web application layer. When users submit requests to the affected endpoint, the application fails to properly validate or sanitize file path parameters, allowing attackers to inject malicious path traversal sequences such as ../ or ..\ that bypass normal access controls. This weakness maps directly to CWE-22, which specifically addresses improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks. The vulnerability operates at the application layer, affecting the web server's ability to enforce proper file system access boundaries and can be exploited through HTTP requests that manipulate file path parameters in the application's API endpoints.
The operational impact of CVE-2020-10086 extends far beyond simple data exposure, as it can lead to complete system compromise when combined with other attack vectors. An attacker who successfully exploits this vulnerability can read arbitrary files on the GitLab server, potentially accessing sensitive information including but not limited to source code repositories, database credentials, configuration files, and system-level data. This exposure creates opportunities for privilege escalation attacks, as attackers may discover authentication tokens, API keys, or other credentials stored in accessible files. The vulnerability can also facilitate further exploitation by allowing attackers to read system files that may contain information useful for lateral movement within the network infrastructure. According to ATT&CK framework, this vulnerability maps to T1083 (File and Directory Discovery) and T1566 (Phishing with Malicious Attachments) as attackers can use the exposed information to craft more sophisticated attacks.
Organizations using affected GitLab versions should implement immediate mitigations to protect their systems from exploitation attempts. The most effective approach involves upgrading to GitLab versions 12.8.2 or later, where the vulnerability has been patched through proper input validation and sanitization of file path parameters. Additionally, implementing network-level restrictions can help limit exposure by blocking access to the vulnerable endpoint from untrusted networks, while also employing web application firewalls to detect and prevent malicious path traversal attempts. Security monitoring should focus on identifying unusual file access patterns or requests containing traversal sequences, as these activities often precede successful exploitation attempts. Organizations should also conduct comprehensive security assessments to identify any other potentially vulnerable endpoints within their GitLab installations and ensure that proper access controls are implemented across all file system interactions to prevent similar vulnerabilities from occurring in other components of their infrastructure.