Ncsc Incident Response Plan Template

Standard Operating Procedure: NCSC-Aligned Incident Response Plan Template

Document ID: SOP-SEC-042
Effective Date: October 24, 2023
Version: 3.1.0
Review Cadence: Semi-Annual
Owner: Chief Architect, Template Registry (Julian Vance)

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1. Executive Summary & Purpose

This Standard Operating Procedure (SOP) defines the operational lifecycle for executing the National Cyber Security Centre (NCSC) Incident Response Plan (IRP) template within enterprise and mission-critical registry environments. The purpose is to establish a deterministic, repeatable, and auditable framework for identifying, containing, eradicating, and recovering from high-severity security incidents while maintaining strict forensic integrity and regulatory compliance.

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2. Scope & Prerequisites

2.1 Scope

This SOP applies to all information systems, cloud workloads, on-premises infrastructure, containerized registries, and personnel operating under Template Registry governance.

2.2 Prerequisites & Tooling

• Access Control: Privileged Access Management (PAM) vault access with break-glass authorization.
• Forensic Tooling: Volatility Framework, Sleuth Kit, tcpdump, Wireshark, AWS CloudTrail/GuardDuty, Azure Sentinel, or SIEM equivalent.
• Communication Channels: Out-of-band encrypted messaging (Signal/Matrix) and dedicated bridge lines.
• Reference Frameworks: NCSC Cyber Assessment Framework (CAF), NIST SP 800-61 Rev. 2.

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3. Roles & Responsibilities (RACI Matrix)

(Legend: R = Responsible, A = Accountable, C = Consulted, I = Informed)

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4. Step-by-Step Procedure

Phase 1: Preparation & Triage (NCSC Stage 1)

• Verify automated SIEM alerting channels and telemetry pipelines are active.
• Validate integrity of immutable log storage and write-once-read-many (WORM) backups.
• Convene the Incident Response Team (IRT) via out-of-band communication upon high-severity alert trigger.
• Classify the incident severity level (Sev 1: Critical Enterprise Impact, Sev 2: Major Operational Impact, Sev 3: Minor/Isolated).

Phase 2: Detection & Analysis (NCSC Stage 2)

• Isolate anomalous network traffic using Security Group/Firewall rule adjustments without powering down hosts (preserving RAM).
• Capture volatile memory (RAM) from suspected endpoints using standardized acquisition scripts (dd, LiME, or OS-native tools).
• Export disk images, hypervisor logs, and cloud control plane audit trails (AWS CloudTrail, GCP Audit Logs).
• Perform IOC (Indicator of Compromise) matching against threat intelligence feeds.
• Document all findings in the centralized chronological Incident Ledger (IR-YYYY-MMDD-ID).

Phase 3: Containment, Eradication & Recovery (NCSC Stage 3 & 4)

• Short-Term Containment: Revoke compromised IAM credentials, terminate active user sessions, and apply micro-segmentation rules to sever lateral movement paths.
• Long-Term Containment: Re-route external traffic through scrubbing centers or maintenance pages if perimeter security is compromised.
• Eradication: Remove malicious artifacts, backdoors, webshells, and unauthorized cron jobs/scheduled tasks.
• Patching: Apply urgent patches or firmware updates to close exploited zero-day vulnerabilities or misconfigurations.
• System Recovery: Restore systems from known-clean, cryptographically verified backups prior to the identified point of compromise.
• Validation: Execute continuous vulnerability scans and integrity checks to confirm threat removal before returning assets to production load-balancers.

Phase 4: Lessons Learned & Post-Incident Review (NCSC Stage 5)

• Schedule the Post-Incident Review (PIR) meeting within 72 hours of incident closure.
• Complete root-cause analysis (RCA) documentation utilizing the "5 Whys" methodology.
• Update detection rules, SIEM Sigma signatures, and automated playbook triggers based on missed telemetry.
• Archive all forensic artifacts, communications logs, and the finalized Incident Ledger into secure cold storage for compliance auditing.

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5. Quality Assurance & Pro-Tips

5.1 Pro-Tips & Best Practices

• Preserve RAM First: Never reboot a live compromised system unless physical safety or catastrophic data destruction is imminent; volatile memory holds critical cryptographic keys and process injection markers.
• Dual-Channel Comm Channels: Assume corporate email and Slack/Teams environments are compromised during an Advanced Persistent Threat (APT) scenario. Always rely on pre-configured, out-of-band channels.
• Chain of Custody: Maintain cryptographic hashes (SHA-256) of all forensic images immediately upon extraction to ensure admissibility in legal proceedings.

5.2 Common Pitfalls to Avoid

• Premature Eradication: Deleting malware before capturing forensic evidence destroys attribution data and root-cause indicators.
• Internal Leakage: Discussing incident details outside the secure IR channel risks tipping off threat actors who may monitor internal communications.

5.3 Metric Thresholds

• Mean Time to Detect (MTTD): $< 15$ minutes for Critical anomalies.
• Mean Time to Isolate (MTTI): $< 30$ minutes from confirmation of compromise.
• PIR Delivery Window: $\le 72$ hours post-resolution.

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6. Frequently Asked Questions (FAQ)

Q: At what point must external regulatory bodies (e.g., ICO, NCSC, GDPR authorities) be notified?
A: Legal and Compliance must be engaged during Phase 2 (Detection & Analysis) for any incident involving PII, financial data, or critical infrastructure disruption. Mandatory notification windows typically begin the moment an incident is verified as a breach (e.g., GDPR 72-hour rule). Do not delay notification to finish internal root-cause analysis.

Q: How should we handle operational disruption if containment requires shutting down core registry services?
A: The Incident Commander holds the authority to execute emergency isolation. If a service outage impacts SLAs, the IC must immediately brief Executive Leadership while initiating redundant failover architectures or displaying maintenance mode portals to end users.