CVE-2016-10130 in libgit2
Summary
by MITRE
The http_connect function in transports/http.c in libgit2 before 0.24.6 and 0.25.x before 0.25.1 might allow man-in-the-middle attackers to spoof servers by leveraging clobbering of the error variable.
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Analysis
by VulDB Data Team • 11/15/2022
The vulnerability identified as CVE-2016-10130 represents a critical security flaw in the libgit2 library's HTTP transport implementation that affects versions prior to 0.24.6 and 0.25.x before 0.25.1. This issue resides within the http_connect function located in the transports/http.c file, where a man-in-the-middle attack vector is created through improper error handling mechanisms. The vulnerability specifically exploits a condition where the error variable gets clobbered during the connection process, allowing malicious actors to potentially impersonate legitimate servers and intercept or manipulate git operations.
The technical root cause of this vulnerability stems from a flaw in how the http_connect function manages error states during the HTTP connection establishment process. When establishing secure connections, the function fails to properly maintain the integrity of error variables that should indicate connection failures or authentication issues. This clobbering behavior creates a scenario where legitimate connection errors are overwritten or masked, potentially allowing attackers to bypass security checks that would normally detect certificate mismatches or unauthorized server responses. The flaw essentially creates a race condition or state corruption where the error handling logic becomes unreliable, enabling attackers to manipulate the connection flow without proper authentication verification.
The operational impact of this vulnerability extends beyond simple data interception, as it fundamentally undermines the security model of git operations that rely on libgit2 for network communications. When exploited, this vulnerability allows attackers to perform man-in-the-middle attacks against git repositories, potentially compromising the integrity of code repositories, source control operations, and development workflows. The attack surface is particularly concerning for organizations that depend on git for version control and collaborative development, as it could enable attackers to inject malicious code into repositories or redirect traffic to compromised servers without detection. This vulnerability affects any application or system that utilizes libgit2 for HTTP-based git operations, including popular tools like GitLab, GitHub Enterprise, and various CI/CD pipelines that depend on secure git protocols.
Mitigation strategies for CVE-2016-10130 primarily focus on immediate version upgrades to libgit2 0.24.6 or 0.25.1 and later, which contain the necessary fixes to address the error variable clobbering issue. Organizations should conduct comprehensive audits of their systems to identify all instances where libgit2 is utilized, particularly in automated build systems, continuous integration environments, and any application that handles git operations over HTTP. Security teams should implement monitoring solutions to detect potential exploitation attempts, and consider deploying network-level controls such as SSL inspection and certificate pinning to add additional layers of protection. Additionally, developers should review their code implementations to ensure proper error handling and validation of connection states when integrating with libgit2, adhering to security best practices that prevent similar issues in custom implementations. This vulnerability aligns with CWE-252, which addresses "Unchecked Return Value" and relates to ATT&CK technique T1571, focusing on "Modify System Image" through manipulation of trusted network connections, highlighting the importance of maintaining secure communication channels in software development environments.