● Given the exposed Docker API and high CPU usage, I strongly recommend starting with a fresh Linode. The privileged container access means attackers could have gained full system control.

  Why fresh start is safer:

  1. Persistent access: Attackers often install backdoors that survive container removal
  2. Rootkit detection: Sophisticated compromises are hard to fully detect and remove
  3. Time vs security: Rebuilding is faster than forensic analysis for production systems

  If you must keep this instance:

  1. Immediate isolation: Disconnect from network, change all credentials
  2. Full forensic analysis: Requires security expertise to ensure complete cleanup
  3. Higher risk: Potential for undetected persistence mechanisms

  For a production CI system, the clean rebuild approach is more secure and time-efficient in the long run.

> What simple steps can I take in the future to make sure this won't happen even as I am setting up my podman containers and testing them?

● Critical Security Steps for Future Setup:

  1. NEVER Expose Docker/Podman API Publicly
  # UNSAFE (what caused the issue):
  podman run -p 2375:2375 --privileged ...

  # SECURE Alternatives:
  # Use UNIX socket (local only)
  podman run -v /var/run/podman.sock:/var/run/podman.sock

  # Or use SSH tunnel for remote access
  ssh -L 2375:localhost:2375 user@host

  2. Firewall First Approach
  # Block all incoming by default
  sudo ufw default deny incoming
  sudo ufw default allow outgoing

  # Only open specific needed ports
  sudo ufw allow ssh
  sudo ufw allow 80,443  # web only if needed
  sudo ufw enable

  3. Avoid Privileged Containers
  # Instead of --privileged, use specific capabilities:
  podman run --cap-add NET_ADMIN --cap-add SYS_ADMIN ...

  # Or use security opts:
  podman run --security-opt=no-new-privileges ...

  4. Test in Isolated Network
  # Create internal network
  podman network create ci-network

  # Run containers on internal network only
  podman run --network ci-network ...

● 5. Monitoring During Setup
  # Watch CPU/memory during testing
  htop

  # Monitor network connections
  sudo ss -tulpn

  # Check container processes
  podman top <container>

  6. Use Temporary Testing Environment
  - Test container configurations on local machine first
  - Use development Linode that can be easily rebuilt
  - Never expose testing containers to public internet

  The key is: never expose container management APIs (Docker/Podman ports) to the internet, and always start with a deny-all firewall policy.