Incident Response (IR) Investigations: What you should focus

When conducting Incident Response (IR) investigations, what you focus on will determine whether you contain a threat fully — or leave your organization exposed to ongoing or repeated attacks.

Focusing your Incident Response investigations on the right areas is essential for determining the scope, root cause, and impact of an incident — and for ensuring it doesn’t happen again.

Here’s a targeted guide to what you should focus on during Incident Response investigations, across technical, procedural, and organizational layers.

Incident Response Investigations: What You Should Focus On

1. Validate the Incident Quickly, Not Just the Alert

Why it matters: Not all alerts are true incidents. Delayed validation wastes time or causes false panic.

Focus on:

• Confirm the legitimacy of the alert (true positive vs. false positive)

• Determine severity and potential business impact

• Identify what data/systems/users are involved

Ask: Is this behavior anomalous for this user or system?

2. Understand the Scope — Not Just the Symptom

Why it matters: Investigating only the first system found means you’ll likely miss others already compromised.

Focus on:

• Lateral movement across endpoints, accounts, cloud environments

• Timeline of the attack: when did it actually start?

• “Patient zero” vs. currently active nodes

Ask: Is this the whole incident response, or just the part we’ve seen?

3. Map to Identity and Access Abuse

Why it matters: Most modern attacks rely on identity — credential theft, privilege escalation, session hijacking.

Focus on:

• Compromised users or service accounts

• Privilege misuse or unusual role changes

• Active sessions (VPN, SSO, API tokens)

Ask: Did the attacker use stolen credentials to move or exfiltrate?

4. Trace the Attacker’s Path (Full Kill Chain)

Why it matters: You need to understand how the attacker entered, persisted, moved, and acted.

Focus on:

• Initial access vector (phishing, exploit, insider, stolen creds)

• Persistence mechanisms (scheduled tasks, registry keys, cloud roles)

• Data exfiltration channels (cloud sync, email, C2, external storage)

Ask: What tools and techniques were used (MITRE ATT&CK mapping)?

5. Preserve and Correlate Evidence

Why it matters: Evidence disappears quickly, and fragmented data prevents solid conclusions.

Focus on:

• Collect logs from EDR, SIEM, firewalls, identity systems, and cloud

• Capture volatile data (RAM, running processes, network connections)

• Maintain chain of custody for forensic integrity for efficient incident response

Ask: Do we have complete logs from relevant systems and time windows?

6. Coordinate with Legal, HR, and Comms (When Needed)

Why it matters: Investigations involving insiders, customer data, or regulated industries need multi-team input.

Focus on:

• Notifying legal early for potential liability or compliance issues

• HR involvement if employees or contractors are involved

• Comms if public disclosure may be needed

Ask: Who needs to know — and when?

7. Document Timelines and Decisions

Why it matters: Good documentation supports forensics, legal defense, and lessons learned.

Focus on:

• Exact timestamps (detection, containment, escalation, response)

• Decision points and rationale (why isolate this, or why delay that)

• Artifacts and evidence collected

Ask: If someone audited this incident response in 6 months, would it make sense?

8. Feed Investigation Findings Back Into Security Improvements

Why it matters: If nothing improves after the incident, you’ll see a repeat.

Focus on:

• Update detections and playbooks

• Address root cause (patch, policy, awareness, tooling gaps)

• Train teams on new tactics or failure points discovered

Ask: What failed — and how can we prevent this next time?

Summary: What to Focus On in IR Investigations