CVE-2024-50338: Git Credential Manager Vulnerability Explained

Microsoft has recently published information about a significant security vulnerability, tracked as CVE-2024-50338, that affects the git-credential-manager. This credential management tool is often bundled alongside Git installations to help developers seamlessly manage authentication credentials for accessing repositories. While this tool makes Git operations painless in terms of user access, it seems "painless" could also mean leaving an attacker the opportunity to expose secrets—or at least in this case—leak sensitive information via malformed URLs.
Let’s break this down, understand the implications, and explore how Windows users and developers can secure themselves against this exploit.

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What is CVE-2024-50338?​

This vulnerability, disclosed on January 14, 2024, revolves around the git-credential-manager and its handling of improperly formatted URLs. When such "malformed" URLs are passed, the application does not sanitize them thoroughly, leading to information disclosure. To put it in simpler terms, this flaw could allow an attacker to deliberately craft a repository URL—dodging expected URL formatting rules—and trick the git-credential-manager into inadvertently leaking sensitive data or authentication credentials.
In the world of Git workflows, that’s huge. The git-credential-manager is designed to store credentials on your behalf, abstracting away manual login and tedious token copying. It creates a pool of trust—but a malformed URL essentially pokes a big hole in that pool, potentially spilling out information to malicious parties.

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How Does the git-credential-manager Work?​

For those unfamiliar, git-credential-manager is an open-source project by Microsoft that manages credentials for HTTP, HTTPS, and GIT-based URLs. Its functionality has grown to cater to modern development environments, particularly advancing the developer experience with Personal Access Tokens (PATs), OAuth authentication, and SSH keys for services like Azure Repos, GitHub, GitLab, and Bitbucket.
Here’s a simplified breakdown of how it operates:

1. Credential Retrieval: It stores credentials securely (in locations like the Windows Credential Manager or, for Mac/Linux users, in secure local storage).
2. Automatic Population: When Git commands like git pull or git push are executed, it fetches and applies the credentials automatically.
3. Sanity Checks: Ideally, tools like git-credential-manager are expected to sanitize and parse URLs before using any sensitive token or key to authenticate. And here is where CVE-2024-50338 plays a role.

The vulnerability shows that malformed (non-standard, erroneous, but deliberately malicious) URLs bypass certain checks, enabling attackers to force git-credential-manager to unintentionally disclose authentication data.

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Real-World Scenarios: Why Should Windows Users Be Concerned?​

If you use Git for Windows or connect to hosted repositories like GitHub or Azure Repos, you’re very likely to have git-credential-manager managing these connections.

Example Scenario:​

Imagine:

1. You clone a repository with the following command:
   
   Code:

   bash
   
      git clone https://malicious[.]example[.]com/repo

2. An attacker has crafted the URL in a specific way. This malformed URL could exploit the git-credential-manager vulnerability.
3. Because the credentials tied to the tool are vulnerable at the parsing stage, the attacker might gain unauthorized access to sensitive credentials tied to your account.

Remember, sensitive credentials can be:

• OAuth tokens
• Personal Access Tokens
• Username-password combinations

In environments where automation and CI/CD pipelines are heavily dependent on stored tokens, this could ripple out into even broader exposures.

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Potential Risks and Threat Scope​

1. Credential Compromise: Attackers could gain access to critical keys or credentials stored locally via the tool, granting them access to private repositories or other secured assets.
2. Pipeline Leakage: In CI/CD setups operated via Git, a leaked key might allow manipulation of internal pipelines, pushing malicious updates into production.
3. Multi-Layered Attacks: With one piece of the puzzle (your credentials), attackers can escalate to broader spear-phishing campaigns against team members.
4. Supply-Chain Concerns: Since GitHub and similar systems are part of most modern software development stacks, such weaknesses amplify risks to the larger supply chain.

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How to Protect Yourself​

Although the patching timeline hasn’t been explicitly detailed here, security advisories like these almost always come with remediation options from maintainers. For now:

1. Update Git and Credential Manager Regularly​

Microsoft, GitHub, and related teams are highly proactive when responding to vulnerabilities. Ensure that the following are updated to their latest versions:

• Your Git client (Git for Windows updates can come bundled with fixes for related tools such as git-credential-manager).
• If you manually installed git-credential-manager, grab the latest release from Microsoft's GitHub repository.

2. Avoid Cloning From Untrusted Sources​

Be cautious about repositories hosted on unknown or insecure platforms—especially if they require authentication. Stick to trusted Git hosting providers.

3. Audit Your Tokens​

Revoke and rotate any Personal Access Tokens or OAuth apps that may have been exposed. Tools like GitHub allow you to view access logs to ensure nothing was compromised.

4. Inspect URLs​

Manually inspect URLs (if possible) before initiating git clone/pull/push commands.

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Broader Implications for Security Enthusiasts​

This vulnerability is an interesting case study in how simple URL parsing—something we often take for granted—can affect application security. For enterprises relying heavily on smooth Git operations, it’s a sharp reminder to maintain a "security-first" approach. Misconfigurations or mishandled dependencies such as credential managers or improperly sanitized variables leave back doors that no one notices.
Moreover, this advisory should resonate with anyone who develops or uses credential-management systems. We've all seen how expansive the responsibilities of such tools can get, given their central role in juggling sensitive data.

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The Call-to-Action for WindowsForum Users​

Now might be an excellent time to share practical insights and solutions with the community. What have you done to protect your development environment from such risks? Is there a broader lesson here about dependency security in open-source tooling? Let’s open up a discussion!
If you’re not sure how to confirm your current configurations or update Git effectively, let me know in the comments—I’d be happy to provide some step-by-step guides. Stay safe out there!

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Source: MSRC CVE-2024-50338 GitHub: CVE-2024-50338 Malformed URL allows information disclosure through git-credential-manager