Third Party Cyber Incident Impact Evidence Checklist

An editable 17-page field guide for the analyst whose vendor has announced a breach and said almost nothing useful. The task is to replace a press statement with an evidence-led view of the affected service, the data and identities involved, the connections into your environment, the timeline, and what remains unknown, so the notification and customer decisions rest on facts. Every item explains why it matters, the result a good answer should produce, the evidence to request, and the next analyst move.

What’s inside

• A readiness page confirming the vendor entity, product, environment, region and service in scope, business criticality and data sensitivity, the internal owners who can validate each claim, and how restricted evidence will be handled
• 30 numbered items, TCI-01 to TCI-30, grouped into 5 control domains and classified as they are in the guide: 28 marked Core and 2 marked Elevated
• Incident Activation and Evidence Control; Vendor Incident Facts and Scope; and Organization Exposure Determination
• Business Legal and Customer Impact; and Recovery Return and Closure
• Response, evidence reference, action owner and due date against every item, so the completed form is the assessment record rather than a questionnaire you transcribe later
• A rapid final checklist that restates all 30 items on one page for the closing challenge

The assessment rule is written into the form: evidence should be current, complete for the service in scope, usable by your organization, tested where capability matters, and linked to a decision. A certificate, policy, screenshot or vendor statement is not enough on its own when it does not prove the specific requirement.