Why Third-Party Cybersecurity Can’t Be an Afterthought

With 30% of breaches now involving third parties, it’s time to rethink your vendor risk strategy.

If your vendors can access your systems, they can also expose you to breach.

The 2025 Verizon Data Breach Investigations Report (DBIR) revealed a sobering truth: 30% of all breaches now involve third-party service providers — double the percentage from the year before. For businesses that rely on Managed Service Providers (MSPs), POS vendors, software integrators, or cloud-hosted tools, this raises a pressing question:

Prevent the vendor from becoming your weakest link? Build a resilient, vendor-aware security posture.

1. Thorough Vendor Risk Assessments
Before integrating any third-party system into your environment, assess:
 ✔️ What access does the vendor have?
 ✔️ Are their systems regularly patched and monitored?
 ✔️ Can they show proof of security controls, such as MFA and encryption?

Align each assessment to industry standards like PCI DSS 4.0.1 and tailor it for your specific environment — whether it’s a convenience store, QSR chain, or any other industry.

2. Documented Security Responsibilities
When a breach happens, everyone asks: who was responsible?
To get an answer clearly document vendor roles and security obligations, including:
✔️ Who manages patching and software updates
✔️ Who handles monitoring and detection
✔️ What happens during incident response
If it’s not in writing, it doesn’t count. You need a clear Roles and Responsibilities document showing what the vendor is responsible for. This is mandatory for PCI DSS 4.0.1.

3. Continuous Monitoring & Visibility
Managed Detection and Response (MDR) and Network Detection & Response (NDR) services provide ongoing visibility into vendor activity across your network — including encrypted traffic and legacy systems where agents can’t be deployed.
If a third party is compromised, you need help to detect it fast and respond even faster.

4. Vendor Inclusion in Incident Response Plans
Under PCI DSS 4.0.1 Requirement 12, vendors who impact cardholder data environments must be included in your incident response plan.
Your plan should account for:
✔️ Clear escalation paths
✔️ Point-of-contact mapping
✔️ Defined roles in forensic investigations
You don’t want to exchange business cards during a crisis.

5. Secure Configurations from the Start
Whether onboarding a new POS, integrating a fuel controller, or setting up remote access, configure systems with vendor risk in mind. That includes:
 ✔️ Disabling unnecessary services
 ✔️ Limiting privileges
 ✔️ Enforcing multi-factor authentication (MFA)
No assumptions — just solid, secure baselines.

Why It Matters
Breaches involving third parties are rising and attackers know the back door is often left ajar. When a vendor drops the ball, it’s your brand, your data, and your customers that take the hit.

Need a downloadable vendor PCI compliance checklist? Get in touch with us. (636) 557-7777 x2407 or x2453.