Authors: S.Choudhuri

Category: Self Published

Date: 14 Aug 2024

Incident‑Response Playbook – Small‑to‑Medium Enterprises (SMEs)

This playbook provides a structured, repeatable process that SMEs can tailor to their size, regulatory environment, and technology stack.

1. Preparation

Activity	Owner	Frequency	Key Deliverables
Policy & Scope Definition	CISO / Management	Annually	IR policy, scope (systems, data, third‑party services)
Incident‑Response Team (IRT) Charter	HR & Security Lead	Annually	Roles (Team Lead, Forensics, Communications, Legal, IT Ops)
Toolset Inventory	IT Operations	Quarterly	EDR, SIEM, backup solutions, forensic kits
Playbook Review & Table‑Top Exercise	Security Lead	Semi‑annual	Updated procedures, lessons learned
Contact Lists	Admin	Quarterly	Internal (team, exec), external (vendors, law enforcement, CERT)
Training & Awareness	HR	Ongoing	Phishing simulations, security awareness modules

2. Identification

1. Alert Reception
   • SIEM, EDR, IDS, user report, or third‑party notification.
2. Triage Checklist
   • What: Type of event (malware, ransomware, data breach, DDoS).
   • Where: Affected assets (IP, hostname, cloud service).
   • When: Time of detection vs. time of occurrence.
   • Impact: Business function affected, data sensitivity.
3. Initial Classification
   • Low – false positive or minor policy violation.
   • Medium – Contained incident, limited scope.
   • High – Potential breach of sensitive data or service outage.

If classification is Medium or High, trigger the formal IR process.

3. Containment

Phase	Actions	Owner	Notes
Short‑Term	Isolate affected host (network segmentation, disable accounts).	IT Ops	Preserve volatile evidence; avoid shutting down power if possible.
Communication	Notify IRT, management, and relevant business units.	Team Lead	Use pre‑approved incident‑notification template.
Evidence Preservation	Capture memory dump, logs, snapshots; hash files.	Forensics	Store in write‑once media or secure cloud bucket.
Long‑Term	Apply patches, change credentials, remediate vulnerable services.	IT Ops & Security	Verify that remediation does not re‑introduce risk.

4. Eradication

1. Root‑Cause Analysis – Identify the vector (phishing email, unpatched service, mis‑configuration).
2. Remove Malicious Artifacts – Delete malware, malicious scripts, compromised accounts.
3. Validate Clean‑Up – Run full scans, compare hash values to baseline, confirm no residual indicators of compromise (IOCs).

5. Recovery

Step	Action	Owner	Success Criteria
System Restoration	Restore from clean backups; verify integrity.	IT Ops	Systems back online with no re‑infection.
Monitoring Ramp‑Up	Increase logging level, enable real‑time alerts for affected assets.	Security	No repeat alerts for 72 h.
User Re‑Enablement	Reactivate accounts after password reset and MFA enforcement.	IT Ops	Users can log in without error.
Business Validation	Confirm critical business processes are functioning.	Business Owner	No reported downtime or data loss.

6. Documenting Lessons

1. Post‑Incident Review Meeting – Within 7 days of containment.
2. Documentation – Update incident log, timeline, and IOCs.
3. Policy Updates – Adjust security controls, patch schedules, or user training based on findings.
4. Report to Stakeholders – Executive summary, impact assessment, cost estimate.

7. Communication Plan

Audience	Message	Channel	Frequency
Internal Staff	What happened, steps taken, any required actions (e.g., password change).	Email / intranet banner	Immediate, then follow‑up as needed
Customers/Partners	If data or service impact, provide transparent status and remediation steps.	Email, status page	Within 24 h of detection
Regulators	Mandatory breach notification (if applicable).	Secure portal / official letter	As required by law (e.g., GDPR 72 h)
Media	Public statement (only if public impact).	Press release	Coordinated with legal

8. Appendices

A. Incident‑Response Checklist (Quick Reference)

[ ] Alert received –> log timestamp

[ ] Triage –> classify severity

[ ] Activate IRT –> notify members

[ ] Contain –> isolate host, disable accounts

[ ] Preserve evidence –> collect logs, memory dump

[ ] Eradicate –> remove malware, patch vulnerability

[ ] Recover –> restore from backup, monitor

[ ] Review –> post‑mortem, update docs

B. Sample Contact List (template)

Role	Name	Phone	Email
Incident Lead	Jane Doe	555‑0101	[email protected]
Forensics Lead	Mark Lee	555‑0123	[email protected]
Legal Counsel	Sara Patel	555‑0145	[email protected]
PR Officer	Luis Gomez	555‑0167	[email protected]
External Vendor (EDR)	XYZ Security	555‑0189	[email protected]