If this package is installed
Remove it, treat the machine (or CI runner) as compromised, and rotate every secret, token and key it could access — from a different, clean machine.
Details
Source: amazon-inspector (70d6b0e13b9995ecb7e5565f8515bdc8148d417fbb797e8a5bd12dcf0d7fbfff)
eth-library-toolkit@2.1.3 presents itself as @ethereumjs/util — README, badges, and the repository URL point at the ethereumjs/ethereumjs-monorepo — but is published under an unaffiliated npm account (azeura <azeura@gmail.com>). The package's dist/index.js unconditionally executes require("commonjs-assertion") at load time, and package.json declares "commonjs-assertion": "^1.2.7" as a runtime dependency in place of the upstream ethjs-util dependency used by the real @ethereumjs/util. commonjs-assertion is not an ethereumjs project and has no functional relationship to the utility APIs this package advertises. Any consumer that installs and requires eth-library-toolkit will resolve and execute whatever code commonjs-assertion currently ships, giving the substituted package arbitrary code execution inside the installer's Node.js process. The impersonation shell plus forced third-party dependency load matches the lookalike-clone-as-delivery-vehicle supply-chain pattern.
Source: ghsa-malware (f0a14281d04c1441978bfb667f8ccb2a937f813404c0afff5dff33cb61b129cf)
Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.