web3-core-jsnpm
Advisory published Updated
web3-core-js is a confirmed malicious npm package (MAL-2026-3719) that typosquats a legitimate package to trick installs (malicious versions 1.0.0, 2.0.0). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in web3-core-js (npm)
What this malware does
package.json declares a lifecycle hook that invokes require('child_process') and execSync with a curl command at install time. This pattern fetches remote content and executes it on the installer's machine as part of npm install, before any user code runs. The package name mimics the widely-used web3/web3-core ecosystem while shipping only a lifecycle trigger for remote execution — no library code consistent with the claimed web3 purpose is present. Running npm install web3-core-js on any developer or CI machine results in arbitrary attacker-controlled bytes being fetched and executed with the privileges of the installing user.
The OpenSSF Package Analysis project identified 'web3-core-js' @ 2.0.0 (npm) as malicious.
It is considered malicious because:
- The package executes one or more commands associated with malicious behavior.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
TyposquatFind it
Search your lockfiles and build artifacts for web3-core-js (2 malicious versions).
If you installed it — respond
web3-core-js is a typosquat — you almost certainly intended a legitimately-named package. Remove web3-core-js, install the correct package, and rotate any secrets exposed during the install since post-install scripts may have already run.
Did it already run?
If web3-core-js was installed, its post-install payload may already have run. Removing the package does not undo that — check outbound connections and credential use from the install window onward.
Frequently asked questions
Campaign
References
Credits
- Amazon Inspector · finder
- OpenSSF: Package Analysis · finder
Detect & block this
O3 blocks web3-core-js-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the malicious outbound activity and severs the channel.