CVE-2008-5916 in Git
Summary
by MITRE
gitweb/gitweb.perl in gitweb in Git 1.6.x before 1.6.0.6, 1.5.6.x before 1.5.6.6, 1.5.5.x before 1.5.5.6, 1.5.4.x before 1.5.4.7, and other versions after 1.4.3 allows local repository owners to execute arbitrary commands by modifying the diff.external configuration variable and executing a crafted gitweb query.
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Analysis
by VulDB Data Team • 08/04/2021
The vulnerability described in CVE-2008-5916 represents a critical command injection flaw within the gitweb component of the Git version control system. This issue affects multiple release branches of Git including 1.6.x before 1.6.0.6, 1.5.6.x before 1.5.6.6, 1.5.5.x before 1.5.5.6, and 1.5.4.x before 1.5.4.7, along with other versions following 1.4.3. The vulnerability stems from insufficient input validation and sanitization within the gitweb.perl script that handles repository browsing functionality. When local repository owners manipulate the diff.external configuration variable and subsequently execute specific gitweb queries, the system fails to properly sanitize user-supplied input before incorporating it into system commands, creating an avenue for arbitrary code execution.
This security flaw operates through a classic command injection vector where the gitweb component directly incorporates user-provided parameters into shell commands without adequate sanitization. The diff.external configuration variable serves as the attack surface, allowing malicious actors to specify external diff programs that can be executed with elevated privileges. When a crafted gitweb query triggers the execution of these external diff programs, the system processes the malicious input as shell commands rather than as simple parameters, enabling attackers to execute arbitrary system commands with the privileges of the gitweb process. This represents a fundamental failure in input validation and command construction that violates core security principles of proper sanitization and privilege separation.
The operational impact of this vulnerability extends beyond simple code execution to encompass full system compromise when the gitweb service runs with elevated privileges. Local repository owners possess the ability to modify configuration files and craft specific queries that exploit this vulnerability, making it particularly dangerous in multi-user environments where repository owners might not be trusted. The vulnerability affects systems where gitweb is configured to allow repository browsing and diff functionality, which is common in development environments, continuous integration systems, and collaborative code repositories. Successful exploitation could result in complete system compromise, data exfiltration, privilege escalation, or the installation of persistent backdoors within the affected infrastructure. Organizations using gitweb for repository browsing are particularly vulnerable since the attack vector requires only local access to modify repository configuration and craft malicious queries.
Mitigation strategies for CVE-2008-5916 should focus on immediate patching of affected Git versions to the latest stable releases that contain the necessary security fixes. System administrators should implement strict input validation for all gitweb configuration parameters and consider disabling the diff.external functionality when it is not essential for repository operations. The principle of least privilege should be enforced by running gitweb processes with minimal required permissions, avoiding execution with elevated privileges. Network segmentation and access controls should be implemented to limit who can modify repository configurations and execute gitweb queries. Additionally, organizations should conduct regular security audits of their Git installations and implement monitoring for suspicious configuration changes or unusual gitweb query patterns. This vulnerability aligns with CWE-77 and CWE-78 categories related to command injection and improper input sanitization, and it maps to ATT&CK techniques involving privilege escalation and execution of malicious code through configuration manipulation. The security community has classified this as a high-severity vulnerability requiring immediate attention due to its local exploitation requirements and potential for significant system compromise.