Automate a Response to GuardDuty Findings
Send GuardDuty findings to an EventBridge rule that isolates the instance so a compromised host is quarantined within minutes.
Task
Configure aws events put-rule --name guardduty-response --event-pattern file://pattern.json --targets file://targets.json so the cloud resource enforces the control automatically without manual console steps.
When to use this
An audit finds that aws events put-rule --name guardduty-response --event-pattern file://pattern.json --targets file://targets.json was configured manually and drifted, leaving a resource exposed for two weeks.
Prerequisites
- Terraform or IaC tooling installed
- Cloud provider credentials with target permissions
Steps
1. Configure aws events put-rule --name guardduty-response --event-pattern file://pattern.json --targets file://targets.json in the project configuration file with the recommended defaults.
aws events put-rule --name guardduty-response --event-pattern file://pattern.json --targets file://targets.json
Expected output: The configuration is accepted and aws events put-rule --name guardduty-response --event-pattern file://pattern.json --targets file://targets.json runs without errors on the first invocation.
2. Run the check locally to verify aws events put-rule --name guardduty-response --event-pattern file://pattern.json --targets file://targets.json produces the expected result before pushing.
pnpm test
Expected output: Local run matches CI behavior; no surprises after push.
3. Add the gate to the CI pipeline so aws events put-rule --name guardduty-response --event-pattern file://pattern.json --targets file://targets.json blocks merge on failure.
- name: Run add guardduty finding automation
run: pnpm test
Expected output: Pull requests with failing aws events put-rule --name guardduty-response --event-pattern file://pattern.json --targets file://targets.json are blocked from merging.
Troubleshooting
Problem
The check passes locally but fails in CI
Solution
Pin dependency versions and the runtime to match CI exactly; reproduce with the same Docker image or act.
Problem
Configuration is rejected with a schema error
Solution
Check the tool version matches the config schema; older versions may not support newer fields.
Limitations
- The gate only runs on events that trigger the workflow; locally pushed commits bypass it.
- Configuration drift is possible if someone edits settings outside version control.
Codify the control
Start by measuring the problem. Send GuardDuty findings to an EventBridge rule that isolates the instance so a compromised host is quarantined within minutes. The most common mistake is adding the gate without first confirming it catches the issue you care about. Run aws events put-rule –name guardduty-response –event-pattern file://pattern.json –targets file://targets.json against the current codebase and inspect the output before wiring it into CI.
aws events put-rule --name guardduty-response --event-pattern file://pattern.json --targets file://targets.jsonDetect drift
Once the gate is in place, make failures actionable. A failing aws events put-rule –name guardduty-response –event-pattern file://pattern.json –targets file://targets.json should point to the exact file and line, not a generic error. Pin the tool version in the lockfile so a upstream release does not silently change behavior. Review the gate output in every pull request just like a test result.