MAL-2026-12056 Malicious code in @zzzgenesis00/mnemonic-to-key (npm)

On npm install, postinstall.js executes and enumerates installer-side secrets: files under ~/.ssh (non-.pub private keys), ~/.npmrc, ~/.gitconfig, Chrome/Chromium/Firefox profile stores (Cookies, Login Data, key4.db), and cryptocurrency wallet directories (.bitcoin,.ethereum,.solana,.metamask,.exodus,.electrum, and similar). It also runs npm whoami and git config user.email and reads a list of credential-shaped environment variables including NPM_TOKEN, NODE_AUTH_TOKEN, GITHUB_TOKEN, AWS keys, MNEMONIC, SEED_PHRASE, ETHEREUM_PRIVATE_KEY, and WALLET_PRIVATE_KEY. The collected data is sent via HTTPS GET to api.telegram.org using a hardcoded bot token and chat_id, with a backup POST to a hardcoded subdomain of serveousercontent.com at path /collect. The postinstall file is disguised with a module.exports = require('./index.js') passthrough and a header comment describing it as environment verification, and exfiltration is delayed with a randomized 1.5–3.5s timer to run after install output completes. Behavior is unrelated to the package's advertised mnemonic-to-key purpose.