Question

Difficulty: MediumIncident Response Process and Playbooks

An incident response team is responding to a confirmed security incident involving unauthorized API key usage and data exfiltration from an enterprise cloud storage bucket. Place the following incident response actions in the correct sequential order from first step to last step according to standard incident response playbooks.

  1. 1Analyze cloud audit logs (CloudTrail) to confirm unauthorized API calls and determine the scope of compromised data.
  2. 2Revoke the compromised IAM access keys and apply a restrictive policy to halt ongoing bucket access.
  3. 3Remove persistent backdoor IAM roles created by the adversary and restore bucket permissions to a secure baseline.
  4. 4Conduct a post-incident retrospective meeting to document the incident timeline and update incident playbooks.

Answer

The correct sequence follows the standard NIST incident response framework: Detection & Analysis (analyzing audit logs to scope the incident), Containment (revoking access keys and locking down storage access), Eradication & Recovery (deleting backdoor IAM roles and restoring secure baseline permissions), and Post-Incident Activity (holding a lessons-learned retrospective and updating playbooks).
The standard incident response process flows sequentially through four main phases: Detection & Analysis, Containment, Eradication & Recovery, and Post-Incident Activity. First, analyzing audit logs establishes incident scope (Detection & Analysis). Second, revoking compromised access keys halts ongoing exfiltration (Containment). Third, deleting unauthorized backdoor roles and restoring baseline permissions removes threat persistence and restores secure operations (Eradication & Recovery). Finally, conducting a post-incident retrospective documents lessons learned (Post-Incident Activity).

Step-by-Step Solution

1
Perform Detection & Analysis
Validate the security event and establish the full scope of compromised cloud resources using audit log analysis.
Before executing containment, responder actions must be guided by verified scope and threat intelligence.
2
Execute Containment strategy
Disable compromised access credentials and restrict bucket access policies to prevent further data loss.
Containment limits damage and prevents the adversary from continuing unauthorized data exfiltration.
3
Perform Eradication & Recovery
Purge any secondary backdoor roles installed by the attacker and return cloud environment permissions to a verified clean state.
Eradication removes all mechanisms of adversary persistence, while recovery restores systems to normal production status.
4
Conduct Post-Incident Activity
Document timeline, evaluate incident response performance, and update playbooks to improve future defense capabilities.
Lessons learned activities occur post-remediation to prevent recurrence and enhance operational readiness.

Key Concept

NIST Incident Response Lifecycle Phases
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