CVE-2016-1901 in CGit
Summary
by MITRE
Integer overflow in the authenticate_post function in CGit before 0.12 allows remote attackers to have unspecified impact via a large value in the Content-Length HTTP header, which triggers a buffer overflow.
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Analysis
by VulDB Data Team • 07/05/2022
The vulnerability identified as CVE-2016-1901 represents a critical integer overflow flaw within the CGit web-based git repository browser software version 0.12 and earlier. This vulnerability specifically affects the authenticate_post function, which processes HTTP POST requests containing git repository data. The flaw manifests when the Content-Length HTTP header contains an excessively large value that exceeds the maximum representable integer value for the system architecture. This condition creates a scenario where the integer overflow corrupts memory boundaries and can potentially lead to buffer overflow conditions within the application's memory management.
The technical implementation of this vulnerability stems from inadequate input validation within the authentication processing pipeline. When CGit receives an HTTP request with a malformed Content-Length header value, the software fails to properly validate or sanitize this input before using it to allocate memory buffers. The integer overflow occurs because the system attempts to convert the large header value into an integer type that cannot accommodate such a magnitude, resulting in wraparound behavior that produces a much smaller integer value than intended. This manipulated value then gets used to determine buffer allocation sizes, creating opportunities for memory corruption and potential code execution.
The operational impact of this vulnerability extends beyond simple denial of service scenarios, as it provides remote attackers with potential pathways for arbitrary code execution within the affected system. Attackers can leverage this flaw by crafting malicious HTTP requests with oversized Content-Length headers, potentially allowing them to overwrite adjacent memory locations, inject malicious code, or manipulate program execution flow. The unspecified impact mentioned in the CVE description reflects the potential for various security consequences including privilege escalation, data corruption, or complete system compromise depending on the execution environment and system configuration. This vulnerability particularly affects web servers hosting git repositories using CGit, making it a significant concern for organizations relying on this software for version control management.
Mitigation strategies for CVE-2016-1901 should prioritize immediate software updates to CGit version 0.12 or later, which contain patches addressing the integer overflow conditions. Organizations should also implement network-level controls including HTTP request size limiting and Content-Length header validation at proxy or firewall levels. The vulnerability aligns with CWE-190, which specifically addresses integer overflow conditions, and can be categorized under ATT&CK technique T1203 for legitimate access exploitation through credential harvesting. Additional defensive measures include implementing input validation frameworks, monitoring for unusual Content-Length header values, and conducting regular security assessments of web applications handling git repository data. System administrators should also consider deploying intrusion detection systems capable of identifying malformed HTTP requests containing suspicious Content-Length values, as this vulnerability can be exploited as part of broader attack campaigns targeting version control systems and development infrastructure.