Incident response is the organized process an organization uses to detect, investigate, contain, remove and recover from a cybersecurity incident. It reduces damage, limits downtime, protects evidence and helps prevent the same incident from happening again.
Common cybersecurity incidents include ransomware, phishing-related account compromise, malware infections, unauthorized access, data theft, denial-of-service attacks and accidental exposure of sensitive information.
The NIST Cybersecurity Framework 2.0 places active response work under Detect, Respond and Recover. CISA's February 2024 guidance also treats an incident response plan as an approved document used before, during and after a suspected or confirmed incident.
Incident Response at a Glance
| Area | Meaning |
|---|---|
| Primary purpose | Control and resolve cybersecurity incidents |
| Typical triggers | Suspicious login, malware alert, data breach, ransomware or system compromise |
| Main activities | Detection, analysis, containment, eradication, recovery and lessons learned |
| People involved | Security, IT, legal, privacy, communications, leadership and external specialists |
| Key document | Incident response plan |
| Main outcome | Reduced business impact and improved future security |
What Does Incident Response Involve?
Incident response usually follows six connected activities:
Detection Identify a potentially malicious or unauthorized event through security tools, employee reports, threat intelligence or an external notification.
Analysis and triage Determine whether the event is a real incident, which systems and data are affected, how severe it is and what priority it requires.
Containment Limit the incident's spread. Responders may isolate a device, disable a compromised account, block malicious traffic or restrict access to a system.
Eradication Remove the attacker's access, malware, persistence mechanisms and other causes of the compromise.
Recovery Restore systems and services safely. The organization should verify that systems are clean and monitor them for renewed activity.
Post-incident improvement Document what happened, preserve evidence, identify control failures and update security measures, procedures and training.
NIST describes the active response functions in its incident response guidance through the NIST Cybersecurity Framework 2.0:
csrc.nist.gov
What Is an Incident Response Plan?
An incident response plan is a documented set of instructions for handling a suspected or confirmed cybersecurity incident.
The plan should identify:
- Who can declare an incident
- Who leads the response
- How employees report suspicious activity
- How incidents are classified by severity
- Which systems may be isolated or shut down
- How evidence and logs are preserved
- When legal counsel, insurers, regulators or law enforcement are contacted
- How customers, employees, suppliers and the media are informed
- How systems are restored and verified
- How lessons learned are recorded
CISA describes an incident response plan as a formally approved document that guides an organization before, during and after a suspected or confirmed security incident:
cisa.gov
A plan on paper does little unless the people named in it know how to use it. CISA recommends maintaining and exercising incident response plans through activities such as realistic tabletop exercises:
cisa.gov
Who Is Responsible for Incident Response?
Incident response is a shared responsibility across security, IT, legal, privacy, communications and leadership. A typical response team may include:
- Security analysts: Investigate alerts, identify threats and coordinate the technical response
- IT and infrastructure teams: Isolate, rebuild and restore affected systems
- Incident response specialists: Conduct forensic investigations and advanced containment
- Legal counsel: Advise on evidence, contracts, privilege and legal exposure
- Privacy and compliance teams: Assess notification and regulatory requirements
- Communications teams: Prepare internal and external messages
- Business leaders: Make decisions about risk, service disruption and priorities
- Cyber insurance providers: Coordinate approved vendors and claim requirements
- Law enforcement: Support investigations where appropriate
CISA recommends involving business leadership and board members in cyber incident planning instead of treating incident response as an IT-only responsibility:
cisa.gov
What Are Common Incident Response Examples?
Incident response actions depend on the type of incident, the systems involved and the evidence available. Common examples include the following.
Ransomware
The response team may isolate infected systems, disable compromised accounts, identify the initial access method, preserve forensic evidence and restore services from trusted backups.
Phishing and Account Compromise
The team may revoke active sessions, reset credentials, enforce multifactor authentication, inspect mailbox rules and determine whether the attacker accessed or sent sensitive information.
Data Breach
The response focuses on identifying the affected data, determining how it was accessed, preserving evidence, closing the vulnerability and assessing notification obligations.
Malware Infection
Responders may quarantine the endpoint, identify related indicators of compromise, check other systems and remove the malware before returning the device to service.
Cloud or SaaS Compromise
The organization may review identity-provider logs, access keys, privileged roles, audit trails, API activity and configuration changes to determine the scope of access.
How Does Incident Response Differ From Related Terms?
Incident response differs from related security and resilience activities in purpose and timing.
| Term | What it means |
|---|---|
| Incident response | The process for handling a cybersecurity incident |
| Incident response plan | The documented instructions used during that process |
| Incident response team | The people responsible for investigating and managing incidents |
| Digital forensics | The collection and analysis of evidence from devices, networks, accounts and systems |
| Disaster recovery | Restoring technology and data after disruption |
| Business continuity | Keeping critical business functions operating during disruption |
| Vulnerability management | Finding, prioritizing and fixing security weaknesses before they are exploited |
| Security operations | Ongoing monitoring and detection activities that may identify incidents |
Incident response investigates and controls the security problem. Disaster recovery restores technology and business services after disruption. Business continuity focuses on keeping essential business functions running while the disruption is being managed.
Why Is Incident Response Important?
Effective incident response helps an organization:
- Detect attacks earlier
- Reduce the spread of malware or unauthorized access
- Limit operational downtime
- Protect sensitive information
- Preserve evidence for investigation
- Coordinate technical and business decisions
- Improve communication during a crisis
- Restore systems in a controlled way
- Identify weaknesses that require remediation
Without a defined response process, an organization may lose time deciding who is responsible, which systems to isolate and whether evidence has been preserved. Those delays can allow attackers to maintain access or increase the damage.
How Can an Organization Improve Incident Response?
An organization can improve incident response by:
- Defining what counts as a security incident.
- Creating severity levels and escalation criteria.
- Assigning named owners and backup contacts.
- Maintaining current asset, identity and vendor information.
- Centralizing logs from important systems.
- Using endpoint, email, network and cloud monitoring where appropriate.
- Protecting and regularly testing backups.
- Preparing playbooks for ransomware, phishing, account compromise and data exposure.
- Agreeing in advance on legal, privacy, communications and law-enforcement procedures.
- Testing the plan with tabletop exercises and updating it after incidents.
Security tools can identify suspicious activity, but people and procedures determine whether the organization contains the incident quickly and recovers safely. The response plan should reflect the systems, suppliers, legal duties and business priorities that apply to that organization.
A Plan Needs Practice
Incident response works when named people, clear decision rules and tested procedures are ready before an alert arrives. Review the plan after exercises, incidents and major changes to systems, suppliers or regulations.