SaaSFort The vendor security assessment guide
Before an enterprise signs with a SaaS vendor, it runs a security assessment: a review of the vendor posture, often a questionnaire plus evidence, sometimes a call with the security team. If you sell into regulated buyers, this is the step that decides whether the deal moves. This guide covers what assessors actually check, the evidence that clears the technical part fastest, and how to walk in already passing.
What a vendor security assessment checks
- 1
External posture
The part anyone can verify from outside: TLS configuration, certificate validity, security headers, DMARC, DNSSEC, and exposed services. Assessors start here because it is observable and hard to fake. A scan answers it directly.
- 2
Compliance and frameworks
Which standards you map to: NIS2 Article 21, ISO 27001 Annex A, SOC 2. A report that maps each finding to these control IDs speaks the assessor language and shortens the review.
- 3
Internal controls and policies
Access reviews, employee training, incident response, supplier management. This part needs your own documentation, not a scan, but assessors weigh it alongside the external evidence.
- 4
Evidence and recency
Assessors trust dated, third-party evidence over self-assertions. A timestamped report that you can re-run shows current state and progress over time, which is exactly what a renewal review wants.
Walk in already passing the external part
The €39 Audit Pack gives you a control-mapped PDF, 90 days of re-scans, and a dated attestation. Run it before the assessment, fix what it flags, and hand the buyer evidence instead of promises. One-time, no subscription.
Frequently asked questions
What is a vendor security assessment?
It is the review an enterprise runs on a supplier before or during a contract to judge security risk. It typically combines a questionnaire (SIG, CAIQ, or a custom set), requested evidence such as certifications and scan reports, and sometimes a call with your security team. The goal is to decide whether onboarding your SaaS introduces acceptable risk.
How do I pass a vendor security assessment as a SaaS vendor?
Clear the external posture first, because it is observable and a common source of easy findings. Run a scan, fix the flagged headers, TLS, and DNS issues, and attach the dated report as evidence. Then prepare your internal-policy documentation for the rows a scan cannot answer. Walking in with evidence rather than assertions is what moves the review fast.
What evidence do assessors actually want?
Dated, verifiable artifacts: a scan report mapped to recognised controls, certifications where you have them, and policy documents for internal controls. For the external section, a third-party scan report mapped to NIS2 Article 21 and ISO 27001 Annex A covers most of what they ask, and it carries a timestamp they can trust.
How is this different from answering a security questionnaire?
The questionnaire is one input to the assessment. The assessment is the whole review: questionnaire, evidence, and judgement. This guide covers the full picture and what assessors prioritise. If you need the step-by-step on answering the questionnaire itself fast, see the security questionnaire response guide.
Related: How to answer a security questionnaire fast · The security evidence pack for enterprise deals · Audit Pack · Scan your domain free (60s)