Incident Response

Lifecycle Phases

Preparation -> Detection and Analysis -> Containment, Eradication, and Recovery -> Lessons Learned and Reporting


  • Create incident response plan
  • Create Incident Response Team
  • Create asset-inventories
  • Run risk assessments
  • Enact defensive measures, eg DMZ, NIDS/HIDS/NIPS, AV, Centralized Logging, EDR, Network Firewalls, Local Firewalls, WAFs, GPOs, NAC, web proxies, SPF/DKIM/DMARC, mark external emails, use email spam filters, DLP, sandboxing, attachment file restrictions, physical defenses, awareness training, phishing simulations, etc...

Detection and Analysis

  • Identify scanning, including:
    • Remote to Local Scanning (R2L): Search for HTTP connections of non standard ports
    • Remote to Local DoS/DDoS (L2R): search for anamolus traffic that differs from baselines
    • Local to Local Scanning (L2L): internal vulnerability scanners
  • Login Failures: search for windows event ID 4625


  • Containment
    • Perimeter containment
      • Block inbound traffic and outbound traffic.
      • IDS/IPS Filters to identify further malicious traffic and take automated actions, such as blocking active connections.
      • Web Application Firewall policies, to detect and take action against web attacks.
      • Null route DNS, to prevent DNS resolutions so internal hosts cannot find the IP address of a given domain name and establish a connection.
    • Network containment
      • Switch-based VLAN isolation, to restrict network access.
      • Router-based segment isolation, to restrict network access.
      • Port blocking, to prevent connections on specific ports.
      • IP or MAC Address blocking, to restrict network access.
      • Access Control Lists (ACLs), to provide rules that restrict what hosts on the network can and cannot do.
    • Endpoint containment
      • Disconnecting the infected system from any network connections (turning WiFi off, pulling ethernet cable).
        • Powering off the infected system.
        • Blocking rules in the local firewall.
        • Host intrusion prevention system (HIPS) actions, such as device isolation.
  • Eradication
    • Remove malicious artifacts
    • Reimage systems
  • Recovery
    • Identify root cause
    • Patch systems
    • Disable uneeded services
    • Update EDR, AV, IDPS, and SIEM rules
    • Share intelligence
  • Lessons Learned and Reporting
    • Post incident review meetings: what could be improved
    • Create report that should contain
      • Executive Summary
      • Incident Timeline
      • Incident Investigation
      • Appendix
      • Report considerations
        • Report Audience
        • Incident Investigation
        • Screenshots and Captions