ISO 27001 Annex A 5.19: Information security in supplier relationships

What auditors look for

Auditors check that 5.19 is either justified as not applicable in your Statement of Applicability or implemented and working. Typical evidence includes:

• Supplier security policy
• Supplier inventory with risk tiers
• Completed security assessments

How to implement 5.19 in practice

1. Tier suppliers by data access and criticality
2. Scale due diligence to the tier
3. Assess before signing, not after
4. Name an owner for 5.19, decide how often it runs and file evidence each time, so the control is audit-ready all year.

How 5.19 supports GDPR

This control helps demonstrate GDPR Art. 28. Map it once in your control matrix so the same evidence supports both ISO 27001 and GDPR accountability. See the GDPR compliance checklist.

Recording 5.19 in the Statement of Applicability

List 5.19 with whether it applies, the reason (usually the risks it treats or a legal or contractual requirement), its implementation status and where the evidence lives. If you exclude it, explain why none of your risks or obligations require it.

Free resources

• Vendor security questionnaire template
• ISO 27001 and GDPR readiness assessment
• 10 steps to implement ISO 27001
• Remote ISO 27001 consultant

More organizational controls

• 5.15 Access control
• 5.16 Identity management
• 5.17 Authentication information
• 5.18 Access rights
• 5.20 Addressing information security within supplier agreements
• 5.21 Managing information security in the ICT supply chain
• 5.22 Monitoring, review and change management of supplier services
• 5.23 Information security for use of cloud services