Vulnerability Exposure Reduction

1. Prerequisites

• Completion of Vulnerability Validation
• Completion of Vulnerability Exposure Assessment
• Inventory of affected assets available
• Access to firewall administration platforms
• Access to cloud administration platforms
• Access to endpoint management platforms
• Access to network administration platforms
• Access to vulnerability management platform
• Access to affected systems and applications
• Incident or tracking ticket created
• Approval for emergency containment actions (if required)

2. Step-by-Step Instructions

1. Review Exposure Assessment

   • Review:
     • Vulnerability details
     • Affected assets
     • Exposure pathways
     • Existing mitigations
     • Business impact
   • Confirm containment priorities.

2. Identify High-Risk Assets

   • Prioritise:
     • Internet-facing assets
     • Production systems
     • Critical business services
     • Privileged infrastructure
   • Document containment scope.

3. Restrict External Access

   • Reduce exposure by:
     • Restricting public access
     • Limiting network exposure
     • Removing unnecessary internet access
     • Restricting management interfaces
   • Validate restrictions.

4. Implement Temporary Security Controls

   • Deploy temporary controls such as:
     • Firewall rules
     • WAF rules
     • IDS/IPS protections
     • Access control restrictions
     • Network segmentation
   • Document all controls implemented.

5. Disable Vulnerable Services

   • Disable or restrict:
     • Vulnerable applications
     • Vulnerable services
     • Unnecessary features
     • Exposed interfaces
   • Validate service status after changes.

6. Restrict Privileged Access

   • Review and restrict:
     • Administrative access
     • Service account access
     • Third-party access
     • Remote access pathways
   • Document changes made.

7. Increase Monitoring Coverage

   • Enable or enhance:
     • Logging
     • Alerting
     • Threat detection rules
     • Network monitoring
   • Ensure monitoring covers affected assets.

8. Validate Exposure Reduction

   • Confirm:
     • Exposure pathways have been reduced
     • Security controls are functioning
     • Vulnerable services are restricted
     • Monitoring is active
   • Document validation results.

9. Document Containment Actions

   • Record:
     • Systems affected
     • Controls implemented
     • Access restrictions applied
     • Validation results
     • Business impact of containment actions
   • Preserve supporting evidence.

10. Escalate and Hand Off

    • Provide containment status to the Incident Commander and Technical Lead.
    • Coordinate with:
      • Remediation teams
      • System owners
      • Infrastructure teams
    • Update the incident record with all actions performed.

3. Post-Action

• Ensure all containment actions are documented.
• Preserve evidence supporting exposure reduction activities.
• Record all temporary controls implemented.
• Track outstanding remediation activities.
• Attach validation results to the incident record.
• Continue monitoring affected assets until remediation is complete.

Contributor

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

Contributed to the Arcana Incident Response Documentation Framework.