Overview
CVE-2023-6528 is a critical security vulnerability discovered in GitHub Desktop and Atom when used in combination with Git Large File Storage (Git LFS). This flaw allows remote attackers to execute arbitrary code on a user’s system by distributing malicious repositories.
Given the popularity of GitHub Desktop in both open-source and enterprise environments, the potential for abuse is high—particularly in supply chain attacks where developers are tricked into cloning and working with compromised repositories.
Understanding the risk and implementing mitigation measures for CVE-2023-6528 is essential for all developers and organizations relying on GitHub Desktop or Atom in their workflows.
Vulnerability Summary
| Field | Detail |
|---|---|
| CVE ID | CVE-2023-6528 |
| Severity | Critical (CVSS Score: 9.8) |
| Attack Vector | Remote |
| Privileges Required | None |
| User Interaction | Required (cloning or interacting with repo) |
| Impact | Remote Code Execution (RCE) |
Affected Products
| Product | Affected Versions |
|---|---|
| GitHub Desktop | < 3.3.4 (macOS), < 3.3.6 (Windows) |
| Atom Editor | All versions (with GitHub + Git LFS) |
How the Exploit Works
This vulnerability is caused by insecure handling of Git LFS configuration and Git hooks during repository cloning or checkout.
Specifically, attackers can craft repositories that embed malicious post-checkout or post-merge hooks within .gitattributes and .git/hooks. When these repositories are cloned or opened using GitHub Desktop or Atom, the malicious code can be automatically executed without alerting the user.
This creates a powerful vector for:
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Installing backdoors or spyware
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Exfiltrating sensitive files or credentials
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Taking control of the developer’s system
The attack is possible because Git LFS was executing hooks embedded in repositories without sufficient validation or sandboxing, thereby allowing arbitrary script execution in a user’s local environment.
Conceptual Example
Below is a simplified conceptual illustration of how this attack may be carried out:
When a developer clones this repository and checks out a branch using GitHub Desktop, the post-checkout hook is silently executed, potentially compromising the system.
Recommendations for Mitigation
To mitigate CVE-2023-6528, users and organizations are advised to take the following steps:
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Upgrade GitHub Desktop
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Windows: Update to version 3.3.6 or later
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macOS: Update to version 3.3.4 or later
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Deprecate Atom
Atom is no longer actively maintained and should be replaced with a supported editor, such as Visual Studio Code. -
Avoid Cloning Untrusted Repositories
Only work with repositories from known sources. Always inspect.gitattributesand.git/hooksmanually if unsure. -
Disable Git Hooks Execution (if possible)
Configure your Git environment to avoid automatic hook execution, or monitor scripts with a sandbox or AppArmor profile. -
Use Endpoint Detection Tools
Systems should be monitored for suspicious process activity originating from Git binaries or developer directories.
Timeline and Response
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Reported: November 2023
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Patched by GitHub: December 2023
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Exploitation in the Wild: No confirmed reports as of the publication date, but the risk remains high
Closing Thoughts
CVE-2023-6528 illustrates how even developer tools can become attack surfaces—particularly when security assumptions are made around common operations like cloning a repo. Developers are encouraged to remain vigilant, enforce strict policies for third-party code, and keep their toolchains up to date.
This vulnerability underscores the importance of secure-by-default practices in dev tooling and the need for continuous auditing of build environments.