Patient 0 (also “index case” or “first identified case”) is the first identified case in a malware outbreak or security incident, representing the initial entry point of a threat into a system, network, or organization. The identification of Patient 0 is crucial for forensic analysis, incident containment, and understanding how the threat spread, allowing incident response teams to track the origin of the attack, identify attack vectors, and implement appropriate containment and remediation measures to prevent further spread of the threat.

What is Patient 0?

Patient 0 is the term used to refer to the first system, user, or device identified as infected or compromised in a security incident.

Characteristics

Identification

  • First case: First confirmed case
  • Origin: Point of origin of the incident
  • Timeline: Start of the timeline
  • Reference: Reference point for investigation

Importance

  • Investigation: Starting point for investigation
  • Containment: Helps in containment
  • Prevention: Improves prevention
  • Lessons: Learning for future incidents

Identification Process

Detection

  • Monitoring: Monitoring systems
  • Alerts: Automatic alerts
  • Analysis: Event analysis
  • Confirmation: Case confirmation

Investigation

  • Forensics: Forensic analysis
  • Timeline: Event reconstruction
  • Traceability: Activity tracking
  • Correlation: Event correlation

Validation

  • Verification: Case verification
  • Documentation: Incident documentation
  • Communication: Finding communication
  • Follow-up: Case follow-up

Use Cases

Malware

  • Virus: First infected system
  • Ransomware: First victim
  • Botnet: First bot
  • APT: First compromise

Incidents

  • Breaches: First exposure
  • Access: First unauthorized access
  • Leaks: First data leak
  • Attacks: First successful attack

Investigation

Methodology

  • Forensics: Forensic analysis
  • Timeline: Temporal reconstruction
  • Traceability: Activity tracking
  • Correlation: Event correlation

Tools

  • SIEM: Event management systems
  • Forensics: Forensic tools
  • Logs: Log analysis
  • Network: Network analysis

Documentation

  • Reports: Investigation reports
  • Evidence: Evidence preservation
  • Lessons: Lessons learned
  • Improvements: Improvement recommendations

Prevention

Monitoring

  • Early detection: Early incident detection
  • Alerts: Alert systems
  • Analysis: Continuous analysis
  • Response: Rapid response

Controls

  • Prevention: Preventive controls
  • Detection: Detection controls
  • Response: Response controls
  • Recovery: Recovery controls

References