MAL-2026-5930 Malicious code in bubblestr (npm)

package.json declares "postinstall": "node index.js", and index.js is a heavily obfuscated single-file script (RC4+base64 string-array with rotating shift and two decoder wrappers). After deobfuscation, the postinstall body performs an HTTP GET to a built URL, writes the response body to a file under os.tmpdir() using fs.writeFileSync(..., {flag:'w+'}), and immediately executes the dropped file via child_process.exec(path, {windowsHide:true, cwd: process.cwd()}). This fires automatically on npm install with no user interaction and lands attacker-controlled bytes on the installer's machine. Author and description fields are empty, the obfuscation has no legitimate justification for a 'utility' package, and the README contradicts the published name by instructing users to install/require @array-util/subsearch — a name-confusion lure designed to harvest installs while hiding under a different documented identity. The combination of install-time remote fetch-and-exec, obfuscation intent to evade scanners, and identity mismatch is a textbook supply-chain dropper.

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.