What Is a PSIR?
A PSIR is a formal process conducted after a security incident to:
- Analyze what happened and why
- Identify root causes and contributing factors
- Evaluate the effectiveness of the response
- Recommend improvements to prevent recurrence
Unlike a technical report, a PSIR focuses on learning and improvement, not blame.
Step-by-Step Guide to an Effective PSIR
1. Assemble a Cross-Functional Team
Include:
- Incident response team
- IT and security operations
- Legal and compliance
- Communications/PR (if applicable)
- Business stakeholders
A diverse team ensures a 360-degree view of the incident’s impact and response.
2. Collect and Preserve Evidence
Gather:
- Security logs and alerts
- Forensic data
- Email and chat transcripts
- Timeline of actions taken
- Screenshots or system snapshots
Ensure evidence is preserved in a secure, tamper-proof manner for legal and audit purposes.
3. Reconstruct the Incident Timeline
Build a detailed timeline that includes:
- Initial detection
- Escalation and containment
- Communication milestones
- Recovery and resolution
This helps identify delays, missteps, or missed detection opportunities.
4. Conduct Root Cause Analysis
Use structured methods like:
- The 5 Whys
- Fishbone diagrams
- MITRE ATT&CK mapping (to understand attacker behavior)
Focus on systemic issues—e.g., lack of MFA, poor logging—not just individual errors.
5. Evaluate the Response
Ask:
- Were detection and alerting systems effective?
- Was the incident escalated appropriately?
- Did the response team follow the playbook?
- Were communications timely and accurate?
Highlight both strengths and weaknesses.
6. Assess Business Impact
Document:
- Downtime or service disruption
- Data loss or exposure
- Regulatory or legal implications
- Reputational damage
Quantifying impact helps prioritize future investments in security.
7. Define and Assign Action Items
Create a list of:
- Technical fixes (e.g., patching, segmentation)
- Policy or process changes
- Training or awareness needs
- Tooling or monitoring improvements
Assign owners and deadlines to ensure accountability.
8. Document and Share the PSIR
Include:
- Executive summary
- Timeline and root cause
- Lessons learned
- Action plan
Share with leadership and relevant teams. Consider anonymizing and sharing lessons across the organization.
9. Follow Up
Schedule a review in 30–60 days to:
- Verify completion of action items
- Test new controls or processes
- Update incident response plans
Continuous improvement is key to building resilience.
Best Practices
- Keep it blameless: Focus on systems and processes, not individuals.
- Standardize the process: Use templates and checklists.
- Involve leadership: Their support is crucial for implementing changes.
- Track trends: Use PSIRs to identify recurring vulnerabilities or gaps.
If you are or have recently experienced a Security Incident and need support contact the Secure Chain Technology Group team today for expert assistance.
