💎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:
The malicious package has a higher version number.
The unclaimed package scope was used, and NPM pulls the package from the public registry.
Proof of Concept (PoC) Steps:
Unclaimed Scope: Suppose the organization
acme-labs
has not claimed its scope on NPM, leaving the package@acme-labs/core-module
unregistered.Attacker Registers the Scope: The attacker can create an NPM account, register the scope
@acme-labs
, and publish a package calledcore-module
with a malicious version, e.g.,99.99.99
.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.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:
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:
This would steal environment variables or other sensitive data from the developer’s machine or CI/CD pipeline, potentially leading to further exploits.
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.
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:
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.
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 yourpackage.json
to ensure that a known, safe version is installed.
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.
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