The Two Main Incident Response Models

The Two Main Models of Incident Response: SANS vs. NIST

Understanding incident response is essential for maintaining an effective cybersecurity program. Before containment or recovery can occur, analysts must first investigate, validate, and understand what has happened. Investigation is not only a core task for cyber defense analysts—it is a foundational capability for any organization responding to cyber incidents.

Two of the most widely referenced incident response models are:

  • The SANS 6-Step Model
  • The NIST 4-Phase Model

Although structured differently, both frameworks share the same goals: confirm the incident, limit damage, remove the threat, restore operations, and improve resilience.

Why Investigation Matters

Accurate investigation determines the success of the entire response effort. Before an organization can contain or remediate an incident, it must first answer the most important question:

Did an incident occur?

Effective investigation enables teams to:

  • Validate whether activity is malicious
  • Determine the scope and impact
  • Identify affected hosts and accounts
  • Analyze attacker behavior and intent
  • Reduce uncertainty in fast-moving situations

Investigation is the bedrock of the entire response process.

SANS vs. NIST: Two Models, One Mission

The SANS 6-Step Model

SANS outlines six discrete phases:

  1. Preparation
  2. Identification
  3. Containment
  4. Eradication
  5. Recovery
  6. Lessons Learned

The NIST 4-Phase Model

NIST organizes response into four broader categories:

  1. Preparation
  2. Detection & Analysis
  3. Containment, Eradication, & Recovery
  4. Post-Incident Activity

Both models emphasize the same operational principles. The difference is simply structure and grouping.

Core Phases of Incident Response

Preparation

Preparation is universally considered the most important phase. It includes:

  • Developing and maintaining the incident response plan
  • Defining roles and communication channels
  • Ensuring logging, monitoring, and evidence sources are available
  • Training responders and conducting tabletop exercises

Good preparation reduces investigation time and confusion during an actual event.

Identification / Detection & Analysis

Once something suspicious occurs, teams must validate the event and determine its nature. This involves:

  • Triage and alert analysis
  • Reviewing logs, telemetry, and artifacts
  • Determining if the activity is malicious or benign
  • Identifying affected assets

Early, accurate identification limits impact and accelerates containment.

Containment

Containment prevents the threat from spreading. Wrong containment strategies—like simply unplugging a system—can disrupt forensics or cause operational issues.

Containment may include:

  • Network isolation of compromised systems
  • Blocking malicious accounts
  • Segmenting or rate-limiting traffic
  • Implementing temporary firewall or policy changes

Containment must be matched to the threat and business impact.

Eradication

Once the threat is contained, responders eliminate the root cause. Common actions include:

  • Removing malware
  • Applying patches
  • Reimaging affected systems
  • Clearing persistence mechanisms
  • Resetting or removing compromised accounts

Eradication must be thorough to prevent reinfection.

Recovery

During recovery, systems return to normal operation. This includes:

  • Verifying that the adversary has been fully removed
  • Restoring services and data from clean sources
  • Monitoring for signs of re-compromise
  • Returning business functions to normal

Recovery focuses on re-establishing stability and confidence.

Lessons Learned / Post-Incident Activity

Every incident provides insight that strengthens future response efforts. Organizations should review:

  • What happened and why
  • How quickly it was detected
  • What worked well
  • Where delays or failures occurred
  • How to improve tools, processes, and plans

This builds organizational resilience and better outcomes over time.

Conclusion

Whether an organization follows the SANS 6-step framework, the NIST 4-phase model, or a customized internal process, the principles of incident response remain consistent. Strong incident response is not just a technical workflow—it is a strategic capability that directly affects business continuity, trust, and long-term security.