CVE-2013-2117 in cgit
Summary
by MITRE
Directory traversal vulnerability in the cgit_parse_readme function in ui-summary.c in cgit before 0.9.2, when a readme file is set to a filesystem path, allows remote attackers to read arbitrary files via a .. (dot dot) in the url parameter.
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Analysis
by VulDB Data Team • 01/04/2022
The CVE-2013-2117 vulnerability represents a critical directory traversal flaw in the cgit web interface software, which serves as a web frontend for git repositories. This vulnerability specifically affects versions of cgit prior to 0.9.2 and resides within the cgit_parse_readme function located in the ui-summary.c source file. The flaw manifests when the system is configured to display readme files from the filesystem, creating a pathway for malicious actors to exploit improper input validation mechanisms. The vulnerability operates by accepting untrusted URL parameters that contain directory traversal sequences, specifically the .. (dot dot) notation, which allows attackers to navigate beyond the intended filesystem boundaries.
The technical implementation of this vulnerability stems from inadequate sanitization of user-supplied input within the cgit_parse_readme function. When a readme file is configured to point to a filesystem path, the application fails to properly validate or sanitize the URL parameter before processing it. This allows attackers to craft malicious URLs containing sequences such as ../../etc/passwd or similar traversal patterns that would normally be restricted by proper file system access controls. The flaw essentially permits arbitrary file reading capabilities by bypassing normal filesystem access restrictions, enabling attackers to access files outside the intended directory scope. This vulnerability directly maps to CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks. The vulnerability can be categorized under the ATT&CK technique T1083, which involves discovering files and directories, and T1566, which covers the initial access phase through the exploitation of remote services.
The operational impact of CVE-2013-2117 extends beyond simple information disclosure, as it provides attackers with the ability to access sensitive system files that could contain credentials, configuration data, or other confidential information. Attackers can potentially read system files such as /etc/passwd, /etc/shadow, or application configuration files that might contain database connection strings, API keys, or other sensitive data. The vulnerability affects any system running cgit versions before 0.9.2 where readme files are configured to point to the filesystem, making it particularly dangerous in environments where cgit serves as a public-facing interface for git repositories. The exploit requires no special privileges beyond basic web access, making it easily exploitable by remote attackers. Organizations using cgit for repository hosting, especially those with public-facing instances, face significant risk of unauthorized data access and potential system compromise through this vulnerability.
Mitigation strategies for CVE-2013-2117 primarily involve immediate patching of affected cgit installations to version 0.9.2 or later, where the directory traversal vulnerability has been resolved through proper input validation and sanitization. System administrators should also implement additional defensive measures including restricting the ability to configure readme files to filesystem paths, implementing proper input validation at all application entry points, and applying web application firewalls that can detect and block directory traversal patterns. The vulnerability highlights the importance of proper access controls and input validation in web applications, particularly those handling file system operations. Organizations should conduct thorough security assessments of their cgit configurations to ensure that readme file paths are properly restricted and that no unnecessary filesystem access is granted to the web application. This vulnerability serves as a reminder of the critical importance of validating user input and implementing proper access controls to prevent unauthorized access to system resources, as outlined in various security frameworks including NIST SP 800-160 and ISO 27001 standards for secure software development practices.