Vendor & Supply Chain Cyber Risk: How to Vet Third Parties Safely

Cyber attacks don’t always start with your organisation.

Increasingly, they begin with a supplier, vendor, or third party that has weaker security controls — and attackers use that access to move sideways into larger or better-protected businesses.

This type of attack is now one of the fastest-growing cyber risks facing UK organisations of all sizes.

In this article, we explain:

Why supply chain cyber attacks are rising
What vendor cyber risk really looks like
Practical steps to vet third parties safely
How UK businesses can reduce risk without slowing operations

All in plain English.

Why Supply Chain Cyber Attacks Are Increasing

Modern businesses rely on dozens — sometimes hundreds — of third parties, including:

IT and managed service providers
Software and cloud service vendors
Payroll, HR, and finance providers
Contractors with system or data access

Attackers target suppliers because:

They often have less mature security
One compromise can unlock access to many customers
Trust relationships reduce suspicion

For cyber criminals, supply chain attacks offer high reward with lower effort.

What Is Vendor & Supply Chain Cyber Risk?

Vendor cyber risk is the risk that a third party’s:

Systems
People
Processes

…could expose your organisation to a cyber incident.

This can happen through:

Stolen credentials
Malware introduced via shared systems
Insecure remote access
Unpatched software
Poor internal security practices

Even if your own security is strong, a weak supplier can undo it.

Common Mistakes Businesses Make

Many organisations:
❌ Assume suppliers are “secure enough”
❌ Trust marketing claims without evidence
❌ Only assess risk at onboarding
❌ Ask overly complex questionnaires that no one reads
❌ Rely on contracts instead of controls

Effective vendor risk management needs to be proportionate and repeatable.

How to Vet Third Parties Safely (Without Overhead)

1. Classify Your Vendors by Risk

Not all suppliers need the same level of scrutiny.

Start by categorising vendors based on:

Access to systems
Access to data
Business criticality

Focus effort where risk is highest.

2. Use Recognised Standards (Not Guesswork)

Rather than inventing your own security requirements, rely on recognised UK standards, such as:

Cyber Essentials
Cyber Essentials Plus
ISO 27001 (for higher-risk vendors)

These provide independent assurance and remove ambiguity.

3. Ask for Evidence, Not Promises

Good questions include:

Are you Cyber Essentials certified?
What is the expiry date?
Is the whole organisation in scope?

Avoid vague answers like “we take security seriously”.

4. Verify Supplier Claims

If a supplier claims Cyber Essentials certification, you can:

Independently verify it using IASME’s Supplier Check tool
Confirm certification status and validity dates

Trust — but verify.

5. Control Access, Not Just Contracts

Ensure suppliers:

Have the minimum access required
Use individual accounts (no shared logins)
Use Multi-Factor Authentication (MFA)
Lose access when contracts end

Technical controls matter more than paperwork.

6. Review Risk Regularly

Vendor risk is not a one-time exercise.

Reassess:

When contracts renew
When scope changes
After security incidents
At least annually for critical suppliers

Cyber Essentials as a Supply Chain Control

Many UK organisations now:

Require Cyber Essentials for suppliers
Include it in procurement policies
Use it as a minimum security baseline

This:

Reduces the likelihood of attacks
Improves consistency
Supports insurance and compliance requirements
Demonstrates due diligence

Why This Matters to Customers and Insurers

Customers increasingly ask:

“How do you manage third-party risk?”

Insurers increasingly ask:

“What controls do you apply to suppliers?”

Being able to demonstrate structured vendor cyber risk management improves trust and reduces friction.

How Fortitude Cyber Helps

At Fortitude Cyber, we help UK businesses:

Identify and prioritise supplier cyber risk
Build practical vendor vetting processes
Use Cyber Essentials effectively across the supply chain
Reduce third-party risk without unnecessary bureaucracy

Our approach is proportionate, practical, and SME-focused.

Protect Your Business from Weak Links

Your cybersecurity is only as strong as the weakest trusted connection.

By taking a structured, sensible approach to vendor cyber risk, you can significantly reduce your exposure to supply chain attacks.

👉 Contact Fortitude Cyber today to discuss vendor and supply chain cyber risk.