What is AWS GuardDuty and where does it fit in a DevSecOps pipeline?
Quick Answer
AWS GuardDuty is used for AWS-native threat detection, running at the runtime stage. Explain the class of problem it catches, why catching it there is cheaper than catching it in production, and how it reports findings back to developers.
Detailed Answer
Describe AWS GuardDuty by the failure it prevents, not by its feature list. It belongs to AWS-native threat detection and runs at the runtime stage of delivery, which matters because the cost of fixing a defect rises sharply the later it is found — the core argument behind shifting security left.
Strong answers cover ML/threat-intel detection over CloudTrail, VPC Flow Logs and DNS logs, EKS and Malware Protection add-ons, finding types and severities, suppression rules to cut noise, and automated response via EventBridge and Lambda. Interviewers also listen for the operational side: who owns the rules, how findings reach the developer who introduced them, how false positives get suppressed without silently disabling coverage, and what the break-glass path is when a fix genuinely cannot ship in time.
Tie it to the wider toolchain. Security scanning is only useful when its output is actionable, deduplicated across tools, and attached to a specific commit, image digest or resource — otherwise teams learn to ignore it.
Code Example
# Where AWS GuardDuty sits in the pipeline # stage: runtime # 1. run the scan against the artifact produced by this stage # 2. compare findings against the agreed severity threshold # 3. auto-isolating an instance on a high-severity finding # 4. publish the report so developers see it on the commit or pull request
Interview Tip
Anchor AWS GuardDuty to a stage and a gate: what it scans, when it runs, and what makes the build stop.