Postmortem for Malicious Packages Published on July 12th, 2018


On July 12th, 2018, an attacker compromised the npm account of an ESLint maintainer and published malicious versions of the eslint-scope and eslint-config-eslint packages to the npm registry. On installation, the malicious packages downloaded and executed code from which sent the contents of the user’s .npmrc file to the attacker. An .npmrc file typically contains access tokens for publishing to npm.

The malicious package versions are eslint-scope@3.7.2 and eslint-config-eslint@5.0.2, both of which have been unpublished from npm. The paste linked in these packages has also been taken down.

npm has revoked all access tokens issued before 2018-07-12 12:30 UTC. As a result, all access tokens compromised by this attack should no longer be usable.

The maintainer whose account was compromised had reused their npm password on several other sites and did not have two-factor authentication enabled on their npm account.

We, the ESLint team, are sorry for allowing this to happen. We hope that other package maintainers can learn from our mistakes and improve the security of the whole npm ecosystem.

Affected Packages

If you run your own npm registry, you should unpublish the malicious versions of each package. They have already been unpublished from the registry.

Attack Method

Further details on the attack can be found here.


With the hindsight of this incident, we have a few recommendations for npm package maintainers and users in the future: