When a cyber event occurs, your most scarce resource is time, while clarity becomes your greatest asset. However, achieving clarity requires intentional effort, cultivated through a systematic investigation process. In the realm of incident response (IR), that clarity comes from following a structured path built around the 3 Pillars of the Incident Response Investigation.
These pillars are not merely steps on a checklist, they are interrelated practices that determine whether your team handles an incident confidently or stumbles through costly missteps.
In this blog, we will explore what each of the 3 Pillars of Incident Response Investigation looks like in practice, why they matter, and how to align them with your enterprise’s response strategy.
Why a Structured Incident Response Approach Still Fails Many Enterprises
Even organizations with mature cybersecurity programs that are familiar with the 3 pillars of incident response investigation struggle to move swiftly from alert to action. Why?
Because most incident response efforts stall at the surface: responding to what’s obvious without fully understanding what’s happening underneath. Investigations become reactive, containment is partial, and remediation feels like a whack-a-mole.
The result? Dwell time stretches. Attackers stay active longer than they should. And recovery becomes more costly than it needs to be.
Here’s the thing: effective IR isn’t just about plugging holes. It’s about understanding the blast radius, isolating the threat, and ensuring it doesn’t come back.
Let’s break that down through the 3 pillars of the incident response investigation.
Pillar 1: Situational Awareness
状況認識 is the foundation of any high-functioning Incident Response investigation. You can’t contain what you don’t fully understand.
This phase is all about gathering context:
- What systems are involved?
- What data might be affected?
- How is the attacker moving laterally, if at all?
- What is the scope and impact?
Modern incident response teams use data from endpoints, networks, and cloud environments. This helps them create a real-time view of threats. Full-packet capture, session reconstruction, and threat intelligence all play a part in understanding the adversary’s behavior.
Pillar 2: Containment
Once the incident is fully scoped, the second step of the 3 Pillars of the Incident Response Investigation comes into picture- containment. That means isolating affected systems and cutting off adversary access without crippling business operations in the process.
There’s a balance here: you need to act fast, but not recklessly.
Common containment actions include:
- Disabling compromised accounts
- Segregating affected network segments
- Blocking malicious IPs or domains at the firewall
- Deploying endpoint isolation protocols
What separates strong IR from weak IR is the ability to contain threats surgically, minimizing disruption while preventing escalation.
This is where the value of predefined incident response playbooks and automated response actions becomes clear. Teams that can trigger containment protocols based on threat type don’t have to reinvent the wheel every time.
Containment isn’t just an IT responsibility. It’s a business continuity move.
Pillar 3: Expulsion, Eradication, and Recovery
Once you’ve established situational awareness and achieved containment, what comes next isn’t just routine “remediation”, it’s a focused campaign to expel the attacker, eradicate their presence, and restore your enterprise with confidence. The basics for this critical phase are:
Attacker Expulsion: Kicking Out the Intruder
First, ensure that the adversary no longer has any access to your environment. This requires coordinated actions across accounts, endpoints, and network controls:
- Disable compromised accounts and credentials.
- Block malicious IPs, domains, and C2 infrastructure that attackers leveraged.
- Find and remove all persistence mechanisms (scheduled tasks, registry modifications, implants, scripts).
- Use forensic and network tools to confirm the attacker cannot re-enter the system.
Eradication: Cleaning Up and Closing Doors
With access blocked and the attacker expelled, the next step is deep cleaning—eliminating all traces and root causes of compromise:
- Malware and artifact removal: Conduct thorough host and network forensics to identify and neutralize any remaining malware, backdoors, or tools left behind.
- Vulnerability management: Identify and patch (or mitigate) the vulnerabilities that allowed the attacker in – don’t just fix symptoms, fix the cause.
- Threat intelligence integration: Feed discovered Indicators of Compromise (IOCs) into your detection systems to prevent immediate recurrence.
Recovery: Validating and Restoring for the Future
The ultimate goal is more than just “back to business”, it’s “back to better business.” Recovery ensures your systems are clean, secure, and your defenses smarter than before:
- Restore clean backups and validate system integrity. Never reintegrate compromised resources without full cleansing and validation.
- Post-incident monitoring: Actively watch for reinfection or signs of lingering adversary presence.
- Lessons learned: Write down what happened. Note how the attacker got in and what helped or hindered them. Use this information to improve detection rules, incident response plans, and training.
- Plan revision and readiness: Use each incident as an opportunity to sharpen your organization’s IR playbooks and capabilities.
This stage sets the tone for institutional learning – the “table stakes” for resilience. If you aren’t kicking attackers out and systematically closing the doors behind them, you’re not just risking recurrence, you’re leaving your enterprise exposed for the next attack.
How NetWitness Supports Enterprise Incident Response Investigations
At this stage, many organizations face a tough question: “Do we have the internal expertise and tooling to handle this ourselves, or do we need support?”
This is where NetWitness Incident Response services offer value beyond the typical outsourced incident response team.
Here’s what NetWitness brings to the table:
- 24×7 global IR readiness with SLA-backed response times
- Access to elite responders with experience across ransomware, supply chain attacks, and APTs
- Deep investigation capabilities, powered by the NetWitness Platform’s full-packet capture and session reconstruction tools
- Collaboration across your IT, security, and compliance teams to align response actions with business impact
Instead of flying blind or overreacting, NetWitness helps enterprises respond with precision and confidence. It is not just about reacting, it’s about investigating smarter, containing faster, and recovering stronger.
You can explore more here: NetWitness Incident Response Services
Final Thoughts: Why These 3 Pillars Still Matter
Attackers adapt. Yet, the basics of IR remain constant.
When dealing with a credential compromise, ransomware, or insider threats, a clear plan is essential. Focus on situational awareness, containment, and remediation. This approach will help your team limit damage and learn quickly.
The 3 Pillars of the Incident Response Investigation aren’t just for the SOC. They’re essential for decision-makers who want faster, smarter responses that don’t just restore operations but improve them.
よくある質問
1. What are the 3 pillars of the incident response investigation?
The 3 pillars of the incident response investigation are situational awareness (understanding the full scope of the threat), containment (preventing further spread), and remediation (eliminating the root cause and securing systems). These form the backbone of any effective investigation process.
2. Why is it important to follow the 3 Pillars of the Incident Response Investigation in sequence?
Each pillar builds on the previous one. Skipping steps leads to blind spots, poor containment, and incomplete remediation.
3. How is remediation different from containment in incident response?
Containment focuses on stopping the attack’s progress—isolating affected systems and blocking adversary movement. Remediation, on the other hand, addresses root causes—patching vulnerabilities, restoring clean backups, and strengthening defenses to prevent recurrence.
4. What are the steps of a strong remediation plan?
An effective remediation plan should:
- Identify and remove persistence mechanisms
- Patch exploited vulnerabilities
- Rotate credentials and reset access
- Rebuild or clean systems
- Document all actions and lessons learned
5. What’s the biggest risk of ignoring the 3 Pillars of the Incident Response Investigation?
Extended dwell time, recurring breaches, and costly downtime due to a lack of structure in your response approach.