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Interview question · Detection Engineering & Incident Response

A standard user account suddenly appears in the Domain Admins group. How do you investigate how it happened and what else changed?

The group change is one event; the question is the chain behind it. The strong answer treats tier 0 as compromised until proven otherwise and works backwards from who made the change and with what credentials.

hardNewPreparation tags: Microsoft, CrowdStrike, Palo Alto NetworksUpdated Nov 2026

The group change is one event; the question is the chain behind it. The strong answer treats tier 0 as compromised until proven otherwise and works backwards from who made the change and with what credentials.

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What would you say before reading the answer?

  1. 01 State the assumptions your answer depends on.
  2. 02 Explain the mechanism and choose a control.
  3. 03 Name a condition that would change your decision.

The worked answer includes an approach, scoring criteria and follow-up questions. Compare the reasoning with your own.

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What if · the follow-ups in this answer

The answer works through 6 follow-ups like an interviewer would

An alert shows a user account was added to Domain Admins outside change control late on a Friday.

  1. How serious is this?
  2. How do you contain?
  3. How do you work backwards?
  4. How do you work forwards?
  5. What if domain-level persistence is suspected?
  6. How would you run the investigation?

Each rung has a nudge, a model answer, the principle that carries over and the weak answer to avoid. Premium opens every answer and ladder.

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