This document outlines a comprehensive response plan for addressing cyber incidents in an IT environment. It guides the Cybersecurity Incident Response Team (CSIRT) through triage, analysis, containment, eradication, restoration, and post-incident activities, while ensuring evidence preservation. The plan is designed for incidents such as unauthorized access, malware, data breaches, or other threats, including scenarios involving third-party systems. By leveraging security monitoring tools and industry best practices, this plan ensures a swift, secure, and legally defensible response to mitigate damage and protect the organization.
Incident Response Checklist
The following checklist summarizes key actions to be completed during a cyber incident response. Refer to the detailed sections below for step-by-step guidance.
Triage
Log a ticket
Acknowledge report of suspicious activity.
Validate incident using security monitoring tools.
Check if the incident involves an external system.
Classify incident severity (low, medium, high).
Assign incident owner in the incident management system.
Preserve evidence for affected systems.
Analysis
Review logs, alerts, and affected systems.
Collect Indicators of Compromise (IOCs) (e.g., IPs, hashes, URLs).
Assess scope of compromise (systems, data).
Engage forensics team for sensitive data or legal cases.
Consult legal counsel for regulatory or litigation risks.
Notify external parties if their systems are involved.
Containment
Isolate compromised systems or accounts.
Reset credentials and enforce strong authentication.
Remove malicious configurations.
Quarantine or remove threats.
Block IOCs in security policies.
Coordinate with external parties.
Eradication
Remove threat actor access.
Remediate vulnerabilities.
Clean affected systems.
Conduct full system review for residual threats.
Monitor for recurring external activity.
Restoration
Restore systems and accounts.
Validate recovery.
Enhance security controls.
Conduct employee training on cyber threats.
Post-Incident Activities
Create incident report.
Conduct lessons learned meeting.
Maintain evidence until approved for release.
Notify regulators/stakeholders if required.
Strengthen defenses.
Close ticket
1. Incident Response Triage
Triage is the initial phase to validate and prioritize the incident, ensuring a rapid response to limit damage.
Log a Ticket
Create a ticket in the incident management system to document the reported suspicious activity and initiate the response process.
Acknowledge Report
Confirm receipt of the report via the ticketing system or direct communication, instructing users to avoid actions that could worsen the issue.
Validate the Incident
Review security monitoring tools (e.g., SIEM, endpoint protection) for alerts, logs, or indicators of compromise (e.g., unusual logins, malicious files).
Correlate signals from network, endpoint, or identity systems to confirm the incident.
Determine if the incident is a false positive (e.g., part of a security test).
Check External Involvement
Identify if the incident involves an external system by analyzing logs or IOCs (e.g., foreign IPs, third-party domains).
Classify Severity
Assign a severity level (low, medium, high) based on impact (e.g., data loss, system disruption).
Escalate high-severity incidents to the CSIRT immediately.
Assign Incident Owner
Assign the incident to a security analyst or team in the incident management system.
Document in a centralized tracking system for visibility.
Preserve Evidence
Preserve evidence on affected systems (e.g., logs, files) to support analysis or legal needs.
Use a compliance platform or secure storage to ensure data integrity.
Verify evidence is protected from tampering or deletion.
2. Analysis
Analyze the incident to determine its scope, impact, and tactics used by the threat actor.
Review Logs and Alerts
Use security monitoring tools to review alerts, logs, and affected systems (e.g., servers, endpoints, accounts).
Analyze logs for suspicious activities, such as:
Unauthorized logins from unfamiliar IPs or devices.
Suspicious configuration changes (e.g., new permissions).
Unusual data access or transfers.
Collect Indicators of Compromise (IOCs)
Gather IOCs like malicious IPs, domains, file hashes, or URLs from logs and alerts.
Use threat intelligence or security tools to identify patterns.
Assess Scope of Compromise
Check for compromised accounts, systems, or data (e.g., altered settings, accessed files).
Investigate network, application, or cloud services for signs of exfiltration or lateral movement.
Determine the attack vector (e.g., phishing, vulnerability exploit).
Engage Forensics Team
If sensitive data or legal implications are involved, engage a forensics team for in-depth analysis.
Preserve evidence (e.g., logs, memory dumps) in a secure, tamper-proof location.
Consult Legal Counsel
If data exposure (e.g., PII, financial records) is suspected, consult legal counsel to assess regulatory requirements (e.g., GDPR, CCPA).
Discuss external system involvement for potential legal coordination.
Notify External Parties
If an external system is involved, identify the third party using IOCs (e.g., domain, IP).
Send a formal notification to their security contact (e.g., security@domain.com).
Include in the notification: timestamp and nature of the incident, relevant IOCs (e.g., IPs, domains), and a request to investigate their system, without sharing sensitive internal data.
Use a professional, neutral tone, noting you have no knowledge of their policies. Example:
Subject: Notification of Potential Cyber Incident Involving Your System
Dear [Organization/Security Team],
We have identified suspicious activity linked to your system ([domain.com or IP]). The incident, detected on [date/time], involves [brief description, e.g., unauthorized access, malware].
To assist your investigation, we are sharing the following indicators of compromise:
- Source: [domain.com or IP]
- Malicious URL: [if applicable]
- File Hash: [if applicable]
We kindly request that you investigate this matter and take appropriate action. Please let us know if you need further details or coordination. We have no knowledge of your internal policies and provide this information to support a secure resolution.
Best regards,
[Your Name]
[Your Organization]
[Contact Information]
Log the notification in your incident tracking system and retain a copy for legal and audit purposes.
If no response is received within 24-48 hours, escalate to legal counsel or consider further coordination steps.
3. Containment
Contain the incident to prevent further damage while preserving evidence.
Isolate Compromised Systems
Isolate compromised systems or accounts (e.g., disable accounts, disconnect devices from the network).
Use identity management systems to block unauthorized access.
Reset Credentials
Reset passwords for affected accounts, enforcing strong, unique credentials.
Enable or strengthen authentication controls (e.g., MFA).
Remove Malicious Configurations
Identify and remove unauthorized configurations (e.g., rogue apps, altered settings).
Review system-wide configurations for suspicious changes.
Quarantine Threats
Quarantine or remove threats (e.g., malware, suspicious scripts) using endpoint protection tools.
Preserve copies of threats in a secure location for analysis.
Block IOCs
Block malicious IPs, URLs, or domains in firewalls or security policies.
Share IOCs with your security team to update defenses.
Coordinate with External Parties
If external parties respond, provide additional IOCs as requested, avoiding sensitive data.
Request updates on their investigation to assess ongoing risk.
4. Eradication
Eliminate the threat actor’s access and mitigate vulnerabilities.
Remove Threat Actor Access
Ensure all compromised accounts, systems, or apps are disabled or reset.
Review configurations for unauthorized permissions or backdoors.