MAL-2026-17640 Malicious code in browser-metrics-plugin.contrib (npm)

browser-metrics-plugin.contrib is a dependency-confusion package: it is described as a "Compatibility shim", uses version numbers up to 99.0.1, and its README calls it an "authorized dependency-confusion test". Each listed version has a postinstall script that runs node beacon.cjs on npm install, and index.js calls the same code when the package is imported; it POSTs the hostname, install path and current working directory over plain HTTP to http://185.158.107.175:8787/_ah/dc, and index.js exports a Proxy that returns no-op functions so builds importing the real package keep running. The npm account xwise8887 published these 6 versions, and 7 versions of troubleshooting with the same payload, on 2026-10-07 between 00:01 and 00:07 UTC.

[email protected] ships beacon.cjs which POSTs a JSON payload containing os.hostname(), __dirname (install path), process.cwd(), and Node version to the hardcoded cleartext bare-IP endpoint http://185.158.107.175:8787/_ah/dc. The beacon fires twice: once from a postinstall lifecycle hook on npm install, and again at require time from index.js (the declared main), which calls require('./beacon.cjs').fire() at top level inside a try/catch. The module exports a Proxy of no-ops so that load failures do not break the surrounding build, concealing the beacon's presence. The second trigger ensures the callback fires even when scripts are disabled via –ignore-scripts. The combination of hardcoded bare-IP destination (no TLS, no domain), host identifier collection at install and import time, dual-trigger design, and silencing wrapper is the canonical dependency-confusion exfiltration shape. A README self-label as a 'research' or 'dependency-confusion test' package is author-controlled and does not constitute installer consent; the hostname and install path disclose internal corporate build infrastructure to a third party.