Mitigating Security Vulnerabilities in GitHub Desktop and Git-Related Projects

 

Introduction

Recent security research has uncovered multiple vulnerabilities in GitHub Desktop and other Git-related projects. If exploited, these flaws could allow attackers to gain unauthorized access to users' Git credentials. The vulnerabilities, collectively termed "Clone2Leak," have the potential to compromise sensitive authentication data and expose systems to further attacks. This article delves into the nature of these vulnerabilities, their potential impact, and the measures available to mitigate risks.

Identified Vulnerabilities

The vulnerabilities, disclosed by Ry0taK, a security researcher from GMO Flatt Security, stem from improper handling of messages in Git's Credential Protocol. This protocol facilitates the retrieval of credentials from the credential helper. Ry0taK’s analysis highlighted multiple vulnerabilities related to credential leakage. The identified flaws include:

• CVE-2025-23040 (CVSS score: 6.6): Maliciously crafted remote URLs can lead to credential leaks in GitHub Desktop.

• CVE-2024-50338 (CVSS score: 7.4): A carriage-return character in remote URLs allows malicious repositories to leak credentials via Git Credential Manager.

• CVE-2024-53263 (CVSS score: 8.5): Git Large File Storage (LFS) enables credential retrieval through crafted HTTP URLs.

• CVE-2024-53858 (CVSS score: 6.5): Recursive repository cloning in GitHub CLI can expose authentication tokens to unauthorized submodule hosts.

Technical Details

The vulnerabilities primarily arise from improper input validation and handling of control characters such as carriage return (\r) and newline (\n). These flaws allow attackers to inject maliciously crafted URLs to manipulate the behavior of the credential helper and exfiltrate credentials.

1. Credential Leakage via Carriage Return Smuggling GitHub Desktop is vulnerable to carriage return smuggling, where a malicious URL can alter the credential request. This results in GitHub Desktop sending credentials to an attacker-controlled host instead of the intended recipient. GitHub’s advisory highlighted that this flaw enables unauthorized access to secrets.

2. Git Credential Manager and Git LFS Weaknesses

   • The Git Credential Manager NuGet package suffers from similar credential leakage issues due to improper handling of control characters. Credentials can be exposed to unrelated hosts.

   • Git LFS does not validate embedded control characters in URLs, permitting carriage return line feed (CRLF) injection and credential leakage via crafted HTTP URLs.

3. GitHub CLI Token Misconfiguration The vulnerability in GitHub CLI leverages the fact that access tokens are sent to non-GitHub hosts if specific environment variables (e.g., GITHUB_ENTERPRISE_TOKEN, GH_ENTERPRISE_TOKEN) are configured and CODESPACES is set to "true." This flaw is particularly concerning when using GitHub Codespaces, as the environment variable is always set to "true" during its execution, making it an attractive target for attackers.

Potential Impact

Successful exploitation of these vulnerabilities allows attackers to:

• Exfiltrate authentication tokens or credentials.

• Gain unauthorized access to privileged resources.

• Potentially launch further attacks against exposed systems.

The severity of the vulnerabilities ranges from medium to high, with CVSS scores reaching 8.5, underscoring the urgency of addressing these issues.

Mitigation Measures

In response to the disclosures, several patches and workarounds have been implemented:

1. Patches Released

   • The Git project has addressed the carriage return smuggling vulnerability (CVE-2024-52006, CVSS score: 2.1) in version v2.48.1. This issue was related to CVE-2020-5260 but exploited a different behavior where carriage return characters were misinterpreted as newlines by some credential helpers.

   • Another vulnerability, CVE-2024-50349 (CVSS score: 2.1), involving escape sequences in crafted URLs, has also been patched in the latest release.

2. Recommendations for Users

   • Update Software: Users should update to the latest versions of GitHub Desktop, Git LFS, GitHub CLI, and other affected tools to safeguard against these vulnerabilities.

   • Avoid Risky Operations: If immediate patching is not feasible, users are advised to avoid running git clone with --recurse-submodules on untrusted repositories. This reduces the risk of exposing credentials to unauthorized hosts.

   • Disable Credential Helper: For added safety, users can disable the credential helper and only interact with publicly available repositories.

Conclusion

The "Clone2Leak" vulnerabilities highlight critical security weaknesses in Git-related tools, emphasizing the importance of robust input validation and secure credential handling. While patches have been issued to address these flaws, users must remain vigilant by updating their tools, following best practices, and minimizing exposure to untrusted repositories. Proactive measures will ensure the protection of sensitive credentials and safeguard systems against unauthorized access.