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Malicious package

fernetsPyPI

Malicious code in fernets (PyPI) Remove it immediately and rotate any exposed credentials.

MAL-2025-191728
Immediate action
Remove the package, then rotate any secrets the build/runtime could reach.
pip uninstall fernets

What this malware does

If imported, the module starts a multi-stage infostealer, exfiltrating browser data as well as crypto wallets, and also attempts to monitor clipboard looking for crypto wallets addresses

Category: MALICIOUS - The campaign has clearly malicious intent, like infostealers.

Campaign: 2025-05-fernets

Reasons (based on the campaign):

  • infostealer

  • clipboard-stealing

  • exfiltration-generic

  • obfuscation

  • exfiltration-browser-data

  • exfiltration-crypto

  • typosquatting

Malicious versions

1 flagged
0.0.1

Indicators of compromise (SHA-256)

dd3b7424b135987d6afd4a7db4a598da28ae35e6bb3f23479895719e7259167e
95fc75ed8a4cfcccc988b2241772effbc15eb3700a6a96f3183981a1b4c7fba7
33de23a7d91f271bac26de71646bc5fa1929e08997ce7ef81d5bdc0bbc45f0d6

Detection & response playbook

Credential / info stealer
  1. Find it

    Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for fernets (version 0.0.1). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging fernets across your stack and pipelines.

  2. If you installed it — respond

    fernets 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.

  3. Did it already run?

    If fernets 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.

  4. How O3 protects you

    O3 blocks fernets 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

No. fernets on PyPI has been identified as a malicious package (version 0.0.1 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

2025-05-fernets

References

Credits

  • Kamil Mańkowski (kam193)

Detect & block this

O3 blocks fernets-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the credential exfiltration and severs the channel.

fernets (PyPI) malicious package — MAL-2025-191728 | O3 Security