In OT cybersecurity, a swift and effective response to a security incident can mean the difference between a minor hiccup and a major catastrophe. But a successful response doesn’t happen by accident. It relies on a well-defined, practiced, and understood process.

Welcome to our “Tech Talk” summary, where we break down complex security topics to help you strengthen your threat hunting and security program. Today, we’re exploring the backbone of cybersecurity operations: the incident response (IR) process. We’ll examine the two most respected and widely adopted best-practice models: the NIST model and the SANS model.

The Two Pillars of Incident Response: NIST and SANS

While several frameworks exist, most modern incident response plans are built upon the foundations laid by the National Institute of Standards and Technology (NIST) and the SANS Institute.

The NIST Incident Response Lifecycle (NIST SP 800-61)

NIST Special Publication 800-61, the Computer Security Incident Handling Guide, is a comprehensive document that outlines everything from creating an IR team to coordinating with external parties. At its core is a four-phase incident response lifecycle:

1. Preparation: Getting your team, tools, and processes ready before an incident occurs.

2. Detection & Analysis: Identifying an incident, determining its scope, and analyzing its characteristics.

3. Containment, Eradication, & Recovery: Isolating the threat, removing it from your environment, and restoring normal business operations.

4. Post-Incident Activity: Learning from the incident to improve future preparedness.

A key feature of the NIST model is its cyclical and flexible nature. The process isn’t strictly sequential. During the “Containment” phase, you may uncover new information that sends you back to “Detection & Analysis” to re-evaluate the scope. This feedback loop acknowledges the reality of complex incidents and builds resilience into the process.

The SANS “PICERL” Model

The SANS Institute offers a similar six-phase model, affectionately known by the acronym PICERL:

1. Preparation

2. Identification

3. Containment

4. Eradication

5. Recovery

6. Lessons Learned

As you can see, the core concepts are nearly identical to NIST. The primary difference is that SANS splits NIST’s “Containment, Eradication, & Recovery” phase into three distinct steps. This is largely a notational difference; the underlying intent and the goals of each stage remain the same across both frameworks.

A Deeper Dive: The Six Phases of Effective Incident Response

Let’s break down each phase, using the granular SANS model as our guide, to understand what it takes to succeed at every step.

Phase 1: Preparation

This is the most critical phase, as it lays the groundwork for everything else. Success here depends on a balanced focus on People, Process, and Technology.

• Technology (The Right Tools): You need analysis tools capable of handling your environment’s data. But a tool is only “right” if your team is trained to use it and your processes allow for its effective deployment.

• People (The Right Skills): Your team members must not only be trained on the tools but also understand their specific roles and responsibilities during a crisis. Do they have the necessary permissions (e.g., domain admin rights) or physical access required?

• Process (The Right Plan): Your IR plan must define who gets involved and when. For example, your process should specify the exact criteria for waking up an executive at 2 a.m. for a critical incident.

Prevention is also a key part of preparation. NIST emphasizes conducting risk assessments, hardening network and host security, and continuous training. These preventative controls reduce the likelihood of an incident and provide valuable data sources if one occurs.

Phase 2: Identification (Detection & Analysis)

Key Metric: Mean Time to Detection (MTTD) – The time from when an attacker acts to when you detect it.

Once an incident begins, the goal is to find it quickly. Success requires:

• Understanding Attack Vectors: Know the general threats (common malware, phishing) and the specific vectors tailored to your organization (e.g., exposed high-risk protocols required for business).

• Identifying Indicators: Based on attack vectors, what indicators of compromise (IOCs) should you be looking for in your logs and alerts?

• Structured Triage: Develop a clear process to distinguish a benign event from a true incident and know when and how to escalate it. Not all incidents are equal—a compromised domain controller is far more urgent than a series of failed login attempts from an external IP.

Phase 3, 4, & 5: Containment, Eradication, and Recovery

Key Metric: Mean Time to Response (MTTR) – The time from the initial detection to full recovery.

This is where the active “response” takes place.

1. Containment: The immediate goal is to stop the bleeding. This involves isolating the affected systems to prevent further damage. This might mean taking a server offline, implementing restrictive firewall rules, or disabling user accounts. Sometimes, containment efforts uncover new aspects of the attack, sending you back to the Identification phase.

2. Eradication: Once contained, you must remove the threat from your environment. This could involve deleting malware, patching vulnerabilities, or even rebuilding systems from a known-good state. It’s crucial to be thorough, as sophisticated attackers often leave multiple backdoors.

3. Recovery: The final step is to restore the affected systems and bring business operations back to normal in a safe and timely manner.

Phase 6: Lessons Learned (Post-Incident Activity)

The incident isn’t over when the systems are back online. This final phase is essential for maturing your security program.

• Conduct Fair and Honest Reviews: Analyze the performance of your people, processes, and technology without placing blame.

• Celebrate Strengths & Identify Weaknesses: What worked well? Pat those teams on the back. Where were the bottlenecks or missed opportunities? Acknowledge them honestly.

• Develop an Actionable Plan: Don’t just document your findings in a report that gathers dust. Create a plan of action with assigned owners and deadlines to implement the lessons you’ve learned.

• Document Everything: Proper documentation is crucial for compliance (e.g., SOC 2), future correlation, and demonstrating program maturity. Consult with legal and policy teams to understand evidence retention requirements.

Conclusion: Building a Resilient Security Program

Both the NIST and SANS frameworks provide a proven roadmap for handling security incidents. By understanding and implementing these phases—from proactive preparation to diligent lessons learned—you can move from a reactive state of chaos to a structured, efficient, and constantly improving incident response program. This structure not only minimizes the impact of an attack but also builds a stronger, more resilient organization over time.

Need help building or refining your incident response plan? The experts at Insane Cyber are here to help. Contact us today to learn how we can strengthen your security posture.