MAL-2026-6353 Malicious code in markdownlint-cli2-fix (npm)

Package name 'markdownlint-cli2-fix' impersonates the popular 'markdownlint-cli2' linter but contains no linter functionality — the README states 'Takeover By lobo / For POC only' and the package ships only postinstall.js plus metadata. postinstall.js (line 30) hardcodes BURP_COLLABORATOR_URL = "http://i0jvc03bvcjt40q39f5fx8671y72vxjm.oastify.com" and, when run, collects host/network reconnaissance (os.hostname(), username, network interfaces, disk info, AD domain info, full process list via ps aux/tasklist through execSync), enumerates Object.keys(process.env) matching a curated credential list (AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY, GITHUB_TOKEN, NPM_TOKEN, STRIPE_SECRET, SSH_PRIVATE_KEY, DEPLOY_KEY, SLACK_TOKEN, DISCORD_TOKEN, JWT_SECRET) plus regex /_(TOKEN|SECRET|KEY|PASSWORD|PWD|APIKEY|API_KEY|PRIVATE_KEY)$/i, and POSTs the JSON payload to the attacker-controlled Burp Collaborator endpoint at oastify.com. While package.json in this version does not declare a scripts.postinstall hook (so the file does not auto-execute on npm install), the package is a deliberate typosquat with no legitimate purpose, the exfiltration code is fully functional, and any installer who is tricked into running the file — or any republish that wires the lifecycle hook — produces immediate credential exfiltration.

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.