CVE-2016-10128 in libgit2
Summary
by MITRE
Buffer overflow in the git_pkt_parse_line function in transports/smart_pkt.c in the Git Smart Protocol support in libgit2 before 0.24.6 and 0.25.x before 0.25.1 allows remote attackers to have unspecified impact via a crafted non-flush packet.
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Analysis
by VulDB Data Team • 11/15/2022
The vulnerability identified as CVE-2016-10128 represents a critical buffer overflow flaw within the libgit2 library's Git Smart Protocol implementation. This security issue affects versions prior to 0.24.6 and 0.25.1, specifically targeting the git_pkt_parse_line function located in transports/smart_pkt.c. The flaw manifests when processing crafted non-flush packets, creating a condition where attacker-controlled input can exceed allocated buffer boundaries. This type of vulnerability falls under the CWE-121 category of stack-based buffer overflow, which represents one of the most common and dangerous classes of memory corruption vulnerabilities in software systems. The Git Smart Protocol is a fundamental component for efficient communication between Git clients and servers, making this vulnerability particularly concerning for distributed version control systems.
The technical exploitation of this buffer overflow occurs during the parsing of packets sent over the Git Smart Protocol, where the git_pkt_parse_line function fails to properly validate the length of incoming data before copying it into fixed-size buffers. When a malicious actor sends a specially crafted non-flush packet containing more data than the allocated buffer space can accommodate, the excess data overflows into adjacent memory regions. This overflow can potentially overwrite critical program variables, return addresses, or other sensitive data structures, leading to arbitrary code execution or denial of service conditions. The vulnerability's impact is amplified by the fact that it operates within a network protocol handler, meaning remote attackers can trigger the flaw without requiring local system access or authentication. The protocol's design allows for the transmission of multiple packet types, but the specific handling of non-flush packets creates an execution path where input validation is insufficient to prevent buffer overflows.
The operational implications of CVE-2016-10128 extend beyond simple denial of service scenarios to potentially enable complete system compromise. When exploited successfully, this vulnerability allows remote attackers to execute arbitrary code on systems running vulnerable versions of libgit2, which is widely used across numerous Git implementations and applications. The attack surface includes any system that relies on libgit2 for Git operations, including development environments, continuous integration servers, and Git hosting platforms. The vulnerability's classification aligns with ATT&CK technique T1203, which describes exploitation of software vulnerabilities for privilege escalation and code execution. Organizations using affected versions may experience unauthorized access to source code repositories, data exfiltration, or complete system compromise. The impact is particularly severe for environments where Git operations are performed over untrusted networks, as attackers can exploit this vulnerability without requiring prior authentication or access to the system.
Mitigation strategies for CVE-2016-10128 focus primarily on immediate version upgrades to patched releases of libgit2, specifically versions 0.24.6 and 0.25.1 or later. System administrators should prioritize updating all affected components and applications that depend on libgit2, particularly those handling Git protocol communications. Additionally, implementing network-level protections such as firewalls and intrusion detection systems can help limit exposure by monitoring and blocking suspicious Git protocol traffic patterns. Organizations should also consider deploying runtime protections and memory corruption detection mechanisms to identify potential exploitation attempts. The vulnerability's remediation aligns with industry best practices outlined in the CWE guidelines for preventing buffer overflow conditions through proper input validation and memory management. Security teams should conduct comprehensive inventory assessments to identify all systems using vulnerable libgit2 versions and establish monitoring procedures to detect potential exploitation attempts. Regular security updates and patch management processes should be strengthened to prevent similar vulnerabilities from remaining unaddressed in the future.