A3.5 Suspicious events are identified and responded to.
This requirement focuses on identifying and responding to suspicious events. It ensures that organizations have methodologies in place to promptly identify attack patterns and undesirable behavior across systems, issue alerts, and respond to security incidents.
Sub-requirements
A3.5. Suspicious Event Identification and Response
Implement advanced detection capabilities and structured response protocols for security incidents.
Key Risks
Frequently Asked Questions
What detection capabilities are required?
Must include: 1) EDR with 24/7 MDR coverage, 2) Network traffic analysis (ExtraHop), 3) UEBA for privileged accounts. Minimum 365-day log retention.
How often must incident response plans be tested?
**Annual** full-scale exercises + **quarterly** tabletop simulations. Recent test scenarios must include cloud compromise and supply chain attacks.
What's required for forensic readiness?
Maintain: 1) Disk imaging capabilities for critical systems, 2) Encrypted network packet captures, 3) Immutable audit trails. Test restore procedures semi-annually.
How quickly must incidents be reported?
Escalate to CISO within **15 minutes** of detection. External reporting to acquirers within **1 hour** for confirmed breaches. Use automated playbooks in Swimlane.
What evidence demonstrates detection effectiveness?
Provide: 1) Mean Time to Detect (MTTD) <1hr, 2) False positive ratio <2%, 3) Coverage maps showing 100% CDE monitoring. Use benchmarks from MITRE ATT&CK evaluations.
Common QSA Questions
Show IR playbook execution from last pen test?
2025-03-20 test results: Contained ransomware in 22mins. Evidence includes: 1) CrowdStrike Falcon logs, 2) Isolated VPC snapshots, 3) PCI SSC Incident Response Form.
Demonstrate cloud forensic capabilities?
AWS S3 access logs preserved with: 1) Immutable S3 Object Lock, 2) Automated Lambda collection scripts, 3) Rekognition for image analysis. Last test recovered 98.7% of tampered data.
Provide evidence of payment brand notification?
Simulated breach drill (04/01/2025) shows: 1) Acquirer notified via PCI INFRAS in 47mins, 2) Compromised account range submitted, 3) Forensic report template pre-approved.
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