← fix library

CRITICAL Jupyter: Jupyter notebook server exposed

Why it matters

An open Jupyter server is a terminal on your machine for anyone who finds it. Bots scan for it constantly (it is one of the most hijacked services on the internet) and use it for crypto mining or as a foothold into the rest of your network.

Fix it — 3 steps

1. Never expose Jupyter directly. Reach it over an SSH tunnel instead: `ssh -L 8888:localhost:8888 user@your-server` and keep :8888 firewalled (`sudo ufw deny 8888`).
2. If it must be remote, put it behind JupyterHub or an authenticating reverse proxy with TLS, and set a strong token or password (never start with --NotebookApp.token='').
3. Check for uninvited guests: running kernels you do not recognize mean someone was already there.

Verify it’s fixed

curl -m 5 http://YOUR_SERVER_IP:8888/api/status  # should be unreachable or demand a token, never answer 200

References

• https://jupyter-notebook.readthedocs.io/en/stable/security.html