Sensitive Data Impact Assessment

1. Prerequisites

• Suspected or confirmed data exfiltration incident
• Completion of:
  • Outbound Traffic Analysis
  • Data Staging Investigation
  • Cloud Storage & SaaS Review (if applicable)
• Access to data classification standards
• Access to data inventory or asset inventory
• Access to data owners and business stakeholders
• Access to SIEM and investigation artifacts
• Access to DLP telemetry (if available)
• Investigation timeline established

2. Step-by-Step Instructions

1. Identify Potentially Impacted Data Sources

   • Identify:
     • File shares
     • Databases
     • Cloud storage repositories
     • SaaS platforms
     • Collaboration platforms
     • Endpoint data stores
   • Document all systems associated with the suspected exposure.

2. Identify Potentially Exposed Data

   • Review investigation findings to determine:
     • Files accessed
     • Files staged
     • Files transferred
     • Data repositories involved
   • Create an inventory of potentially exposed information.

3. Determine Data Classification

   • Classify identified data according to organisational standards.
   • Determine whether exposed data includes:
     • Public data
     • Internal data
     • Confidential data
     • Restricted data
     • Regulated data

4. Assess Regulated Data Exposure

   • Identify whether exposed data contains:
     • Personally Identifiable Information (PII)
     • Financial information
     • Health information
     • Government-regulated information
     • Contractually protected information
   • Document all regulatory implications.

5. Assess Intellectual Property Exposure

   • Determine whether exposed data includes:
     • Source code
     • Proprietary algorithms
     • Research data
     • Product designs
     • Strategic business information
   • Assess potential business impact.

6. Identify Affected Business Units

   • Determine:
     • Data owners
     • Business units impacted
     • Customers impacted
     • Partners impacted
   • Notify relevant stakeholders.

7. Assess Exposure Scope

   • Estimate:
     • Number of files exposed
     • Number of records exposed
     • Volume of data exposed
     • Duration of exposure
   • Document assumptions and confidence levels.

8. Assess Business Impact

   • Evaluate potential impacts including:
     • Operational disruption
     • Financial impact
     • Legal impact
     • Regulatory impact
     • Reputational impact
   • Assign an overall impact assessment.

9. Prepare Impact Assessment Summary

   • Document:
     • Impacted datasets
     • Data classifications
     • Regulatory considerations
     • Business impact assessment
     • Exposure estimates
   • Prepare summary for Incident Commander and stakeholders.

10. Escalate and Hand Off

    • Provide findings to:
      • Incident Commander
      • Legal & Compliance
      • Data Owners
      • Executive Stakeholders (if required)
    • Escalate to:
      • Escalation, Legal & Executive Communications
      • Recovery and Exposure Mitigation activities
    • Update the incident record with all findings.

3. Post-Action

• Ensure all impacted datasets are documented.
• Ensure data classifications are recorded.
• Preserve supporting evidence and investigation artifacts.
• Document all assumptions and confidence levels used during assessment.
• Attach the final impact assessment to the incident record.
• Support legal, compliance, and regulatory review activities as required.

Contributor

Vishal Thakur GitHub: https://github.com/malienist

Contributed to the Arcana Incident Response Documentation Framework.