OpenSSF/OSV advisory MAL-2026-14221 confirms this npm version as malicious. ssb-test-package@1.0.0 is a dependency-confusion proof-of-concept. package.json declares `preinstall: node poc.js`, and poc.js runs unconditionally on `npm install`, collecting host reconnaissance (OS user, hostname, platform, arch, Node version, cwd, and non-internal network interface addresses) into a JSON `proof` object with `rce_status: "CONFIRMED"` written to /tmp/npm-dependency-confusion-rce-poc.json...
Source
OpenSSF Malicious Packages via OSV
Summary
Malicious code in ssb-test-package (npm)
Details
ssb-test-package@1.0.0 is a dependency-confusion proof-of-concept. package.json declares `preinstall: node poc.js`, and poc.js runs unconditionally on `npm install`, collecting host reconnaissance (OS user, hostname, platform, arch, Node version, cwd, and non-internal network interface addresses) into a JSON `proof` object with `rce_status: "CONFIRMED"` written to /tmp/npm-dependency-confusion-rce-poc.json. The package has no legitimate library functionality: package.json declares `main: index.js` but index.js is absent from the tarball; only package.json and poc.js are shipped. The package self-identifies as a PoC for npm dependency confusion using a look-alike internal name. The current build writes reconnaissance data locally and does not exfiltrate over the network, but the preinstall hook demonstrates arbitrary code execution on the installer's host at install time.
Decision reason
OpenSSF Malicious Packages via OSV confirms ssb-test-package@1.0.0 as malicious (MAL-2026-14221): Malicious code in ssb-test-package (npm)