CVE-2024-24577 in libgit2
Summary
by MITRE • 02/07/2024
libgit2 is a portable C implementation of the Git core methods provided as a linkable library with a solid API, allowing to build Git functionality into your application. Using well-crafted inputs to `git_index_add` can cause heap corruption that could be leveraged for arbitrary code execution. There is an issue in the `has_dir_name` function in `src/libgit2/index.c`, which frees an entry that should not be freed. The freed entry is later used and overwritten with potentially bad actor-controlled data leading to controlled heap corruption. Depending on the application that uses libgit2, this could lead to arbitrary code execution. This issue has been patched in version 1.6.5 and 1.7.2.
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Analysis
by VulDB Data Team • 11/16/2024
The vulnerability CVE-2024-24577 represents a critical heap corruption flaw within the libgit2 library that enables remote code execution through improper memory management during index operations. This issue specifically affects the `git_index_add` function which is fundamental to Git's indexing mechanism, allowing applications that integrate libgit2 to process potentially malicious input data. The vulnerability stems from a flaw in the `has_dir_name` function located in `src/libgit2/index.c` where an entry is prematurely freed without proper validation of its usage context. This memory management error creates a classic use-after-free condition that can be exploited by attackers to manipulate heap metadata and control program execution flow.
The technical exploitation of this vulnerability relies on the improper handling of memory allocation and deallocation within the Git index processing pipeline. When `git_index_add` processes malformed input data, the `has_dir_name` function incorrectly identifies certain entries as eligible for deallocation while these entries remain referenced elsewhere in the code path. The freed memory block is subsequently reallocated and overwritten with attacker-controlled data, creating opportunities for heap spraying and controlled memory corruption. This flaw aligns with CWE-416, which categorizes use-after-free vulnerabilities as a serious memory safety issue that can lead to arbitrary code execution. The vulnerability demonstrates characteristics consistent with ATT&CK technique T1059.007, where adversaries leverage memory corruption vulnerabilities to execute malicious code through compromised applications.
The operational impact of CVE-2024-24577 extends across numerous applications that depend on libgit2 for Git functionality including version control systems, continuous integration platforms, and development tools. Applications such as GitLab, GitHub Enterprise, and various CI/CD pipelines that utilize libgit2 internally become vulnerable to remote code execution attacks when processing untrusted repository data or user inputs. The vulnerability's exploitation potential is particularly concerning because it can be triggered through normal Git operations without requiring elevated privileges, making it accessible to attackers who can influence repository contents or manipulate Git operations. The patched versions 1.6.5 and 1.7.2 address this issue by implementing proper memory management checks and ensuring that freed entries are not accessed or overwritten by subsequent operations, thereby preventing the heap corruption scenario that enables arbitrary code execution.
Organizations should prioritize immediate patching of all systems utilizing affected versions of libgit2 to mitigate this vulnerability. Security teams should conduct comprehensive vulnerability assessments across their software ecosystems to identify applications that depend on vulnerable libgit2 versions, particularly those handling untrusted Git data or user inputs. The remediation process should include thorough testing of patched versions to ensure compatibility with existing applications while maintaining security posture. Additionally, organizations should implement monitoring for suspicious Git operations and consider implementing network segmentation controls to limit potential exploitation vectors. This vulnerability serves as a reminder of the critical importance of memory safety in C-based libraries that handle untrusted data, emphasizing the need for rigorous code review processes and automated memory safety testing in security-critical components.