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Case E73A5D · AI security · L2 Practitioner

The Package That Should Not Exist

Practise as: Incident drill · InterviewLevel: L2 Practitioner

Live alertEDR flags a build agent making outbound connections from a postinstall script. The package, "fastapi-auth-helpers", was added in a pull request whose description says an AI assistant suggested it. It was first published to PyPI 9 days ago.

Interview questionA dependency suggested by an AI assistant turned out to be malicious. How do you respond?

  1. 01 What happened?
  2. 02 What is the impact?
  3. 03 What do you do?
Practise this card As Interview
What a strong answer covers

Try it out loud first. Then check yourself:

  1. Contain: stop the pipeline, isolate the build agent, and rotate every secret the agent could read.
  2. Scope: find every repository, build and developer machine that installed the package, and what the script did.
  3. Check artifacts built since it was added: anything from that agent may be tampered with and need rebuilding.
  4. Prevent: new dependencies need review, builds pull from a vetted internal mirror, and installs run with no secrets in reach.

If the interviewer pushes back

  • How would you tell PyPI and other affected users, and why does it matter?

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Reviewed 2026-10-09