Robert Derby
Senior Security Product Marketing Manager
Understanding Incident Response
Incident response is the coordinated process an organization uses to prepare for, identify, contain, recover from, and learn from a cybersecurity incident.
It brings together people, processes, and technology so teams can understand what happened, limit the impact, restore normal operations, and reduce the chance of the same problem happening again.
Incident response is not solely a technical security exercise. Depending on the severity of the incident, it can involve security, IT, networking, legal, compliance, communications, business leaders, and external specialists.
The goal is simple: respond effectively while limiting business impact.
Why Is Incident Response Important?
Security controls can reduce risk, but no organization can assume every attack or security failure will be prevented.
When an incident occurs, the quality of the response can determine how disruptive it becomes.
A strong incident response capability helps organizations:
- Confirm whether suspicious activity is actually an incident
- Understand what happened and what is affected
- Limit further damage
- Coordinate actions across technical and business teams
- Restore affected systems safely
- Preserve evidence for investigation or reporting
- Learn from the incident and improve future readiness
Speed matters, but speed without understanding can create new problems. Disconnecting the wrong system, disabling a critical account, or restoring operations too early can make an incident worse.
Effective incident response balances urgency with informed decision-making.
Security Event vs Incident vs Breach
These terms are related, but they are not interchangeable.
- A security event is an observable occurrence, such as a login attempt, network connection, configuration change, or security alert.
- A security incident occurs when activity threatens or violates the confidentiality, integrity, or availability of systems or information, or violates security policies.
- A data breach generally refers to an incident involving unauthorized access to or disclosure of protected or sensitive information.
Many security events do not become incidents. Not every incident becomes a breach.
One of the first jobs of incident response is determining which situation the organization is actually dealing with.
Incident Response vs. an Incident Response Plan
Incident response is the overall discipline.
An incident response plan is the documented guidance that helps an organization carry it out. It typically defines responsibilities, escalation procedures, communication requirements, decision authority, and other expectations before an incident occurs.
Organizations may also develop incident response playbooks for common scenarios such as ransomware, compromised credentials, phishing, malware, or data exfiltration.
The plan establishes how the organization operates. Playbooks provide guidance for specific situations. Incident response is what happens when those plans are put into action.
What are the Phases of Incident Response?
Different frameworks describe incident response in different ways.
The commonly referenced SANS model includes six phases:
- Preparation: Establish plans, responsibilities, tools, communications, and procedures before an incident occurs.
- Identification: Determine whether suspicious activity represents an incident and assess its severity and scope.
- Containment: Limit the incident's ability to cause additional damage.
- Eradication: Remove malware, unauthorized access, compromised credentials, vulnerabilities, or other causes of the incident.
- Recovery: Restore affected systems and services while monitoring for signs that the threat remains.
- Lessons learned: Review what happened, how the organization responded, and what should change.
NIST updated its incident response guidance in SP 800-61 Revision 3 in 2025. Its current approach aligns incident response with the NIST Cybersecurity Framework 2.0. Detect, Respond, and Recover form the core incident response lifecycle, while Govern, Identify, and Protect support preparation and broader cybersecurity risk management.
The terminology differs, but the principle is consistent: prepare, understand the incident, limit its impact, restore operations, and learn from it.
What Happens During an Incident Response?
Real incidents rarely follow a perfect sequence.
New evidence can expand the scope of an investigation. A containment action may reveal another affected system. Recovery may uncover activity that was missed earlier.
Most responses revolve around a few fundamental questions:
- Is this actually an incident?
Teams validate the initial signal and determine whether further action is required. - What happened?
Responders examine relevant evidence to understand how the activity began and what occurred. - What is affected?
Teams determine which systems, accounts, applications, data, or environments are involved. - How can further damage be limited?
Responders may isolate systems, disable accounts, block communications, change credentials, or apply other controls. - What needs to be removed or fixed?
This may include malware, unauthorized access, vulnerable systems, compromised credentials, or persistence mechanisms. - Can normal operations be restored safely?
Systems may need to be rebuilt, restored, tested, and monitored before returning to production. - What should change afterward?
Teams review the incident and improve controls, processes, visibility, training, and response procedures.
Who is Involved in Incident Response?
Cybersecurity teams often coordinate the response, but serious incidents rarely stay within the Security Operations Center (SOC).
Participants may include:
- Security operations and incident response teams
- IT and infrastructure teams
- Network teams
- Identity and access management teams
- Cloud and application teams
- Digital forensics or threat hunting specialists
- Legal, privacy, and compliance teams
- Communications and public relations
- Business and executive leadership
- External incident response specialists
The exact team depends on the incident.
What matters is that responsibilities and decision authority are clear before a high-pressure situation occurs.
What Tools are Used During Incident Response?
Incident responders usually rely on several technologies within their security stack because these technologies provide a different view and/or capability of an incident.
Common sources include:
- SIEM for collecting and correlating logs and security events
- EDR and XDR for endpoint and cross-domain investigation
- NDR for network-based activity and communications
- Identity security tools for authentication and access activity
- Cloud security platforms for cloud workloads, services, and identities
- Threat intelligence for context about indicators and attacker behavior
- Packet capture and network forensics for reconstructing network activity
- SOAR for coordinating and automating defined response workflows
Each source answers different questions, but they are not interchangeable.
Endpoint data can show what occurred on a managed device. Identity systems can show who authenticated and how access was used. Cloud and application logs can explain activity within those environments.
Network visibility provides something different: evidence of how systems actually communicated with one another.
That makes network data especially important when responders need to understand activity across systems, trace east-west movement, investigate managed or unmanaged assets, or determine whether suspicious behavior extended beyond the endpoint or application where the incident was first detected.
During incident response, that broader view can be critical to establishing scope.
What Makes Incident Response Difficult?
Some of the most common challenges include:
- Incomplete visibility: Teams cannot investigate what they cannot see or what was not retained.
- Fragmented evidence: Relevant information may exist across endpoint, identity, network, cloud, application, and security platforms.
- Unclear scope: Identifying the first affected system does not necessarily reveal every system or account involved.
- Unclear ownership: Teams lose time when responsibilities, escalation paths, or decision authority are not defined.
- Business disruption: The fastest containment action may not be the safest operational decision.
- Poor preparation: Plans that have never been tested often break down during real incidents.
- Missing historical context: Investigators may know what is happening now without knowing what happened before the initial detection.
Strong incident response programs address these problems before an incident forces them to.
Incident Response Best Practices
Organizations can improve incident response by focusing on a few fundamentals:
- Define roles, escalation paths, and decision authority
- Maintain and regularly test an incident response plan
- Build playbooks for common incident types
- Understand what evidence is available and how long it is retained
- Maintain accurate information about critical systems and dependencies
- Document key decisions and actions during the response
- Conduct post-incident reviews
- Turn lessons learned into changes in security controls, processes, and training
The best incident response programs continuously improve.
Why is Network Visibility Critical To Incident Response?
Incident response depends on understanding how activity moved across the environment, not just what happened on an individual system.
That is where network visibility becomes critical.
Endpoint, identity, application, and cloud telemetry provide valuable evidence, but each reflects activity from the perspective of the system generating the data. Network traffic shows the communications connecting those systems.
During a threat investigation, that can help responders answer questions that are fundamental to determining scope:
- What systems communicated with the affected host?
- Where did the activity originate?
- Did it move laterally to other systems or network segments?
- Did the system communicate with unexpected external destinations?
- Was similar activity occurring elsewhere?
- What happened before the original alert was generated?
Network visibility can fill important evidence gaps when endpoint telemetry is unavailable or incomplete, such as with unmanaged devices, network infrastructure, IoT/OT systems, or other assets that cannot run endpoint agents. It can also expose communications across internal network segments that perimeter-focused security controls may not see.
Historical network evidence is particularly important. The first alert rarely marks the true beginning of an incident. Responders often need to look backward to understand what happened before detection, then follow communications forward to determine how far the activity spread.
Network visibility is therefore more than another source of security data. It is a critical part of establishing what happened, where activity moved, and how broadly an incident may have affected the environment.
How Can NETSCOUT Help?
NETSCOUT’s Omnis Cyber Intelligence provides network-based evidence that can support incident validation, investigation, scoping, threat hunting, and retrospective analysis.
Omnis Cyber Intelligence analyzes traffic through distributed sensors located where network traffic is captured. It preserves packet-derived data and packet evidence that analysts can use to examine activity before, during, and after a security event.
During an incident, this can help teams investigate communications involving affected systems, reconstruct sequences of activity, examine east-west traffic, and determine whether suspicious behavior extended elsewhere in the observed environment.
That network evidence complements SIEM, EDR, XDR, identity, cloud, and other security technologies. Those systems may identify the original signal or provide evidence about a particular host, account, or application. Network visibility helps responders connect activity across those systems and understand how the incident moved through the environment.
NETSCOUT's role is not to replace the incident response process or the other technologies involved in it. It is to fill in the evidence gap, by providing the network evidence responders need when understanding communication, movement, and scope becomes critical to the investigation.
Frequently asked questions
- What is incident response in cybersecurity?
- Incident response is the process organizations use to prepare for, identify, contain, recover from, and learn from cybersecurity incidents.
- What is the goal of incident response?
- The goal is to limit the impact of a cybersecurity incident, restore normal operations, and improve the organization's ability to respond to future incidents.
- What are the six phases of incident response?
- The commonly referenced SANS model includes preparation, identification, containment, eradication, recovery, and lessons learned.
- What is the difference between incident response and an incident response plan?
- Incident response is the overall discipline and activity. An incident response plan documents how the organization intends to carry out that response.
- Who is responsible for incident response?
- Security teams often coordinate the response, but IT, networking, legal, compliance, communications, business leaders, and external specialists may also be involved depending on the incident.