The Four Ways Your Suppliers Introduce Cyber Risk to Your Business

When businesses think about third-party cyber risk, they often start with their technology vendors.

Who has access to our network? Which software providers do we use? Which IT partners could introduce a vulnerability?

Those are important questions. But they don’t capture the full picture.

A supplier doesn’t need access to your network to create significant cyber risk for your organization. A cyberattack against a critical manufacturer could interrupt your production. A breach at a payroll provider could expose employee data. An incident involving a customer-facing platform could disrupt a service your customers associate directly with your organization.

That’s why SensCy looks at third-party cyber risk through a broader lens.

We call it the Four Box methodology: four ways a supplier, vendor or business partner can introduce cyber risk to your organization.

Let’s examine each of the “boxes.”

Core Question: How connected is the supplier to your technology environment?

Many organizations give third parties access to systems, applications and networks to provide essential services. Managed IT providers, enterprise resource planning (ERP) partners and other technology vendors may require significant access to do their jobs.

That connectivity creates risk.

If a supplier with trusted access is compromised, an attacker may be able to use that relationship as a pathway into your organization.

What it can look like: Okta and Cloudflare

In 2023, attackers gained access to Okta’s customer support system and obtained an authentication token associated with Cloudflare. According to Cloudflare, the attackers were able to use the compromised token to access Cloudflare’s Okta instance. Cloudflare detected and contained the activity before customer information or production systems were affected.

The incident illustrates an important third-party risk: the more deeply a supplier is integrated into your environment, the more important it is to understand the risk associated with that connection.

As you examine your supplier list with respect to this box, ask:

• Which suppliers have access to your network or internal systems?
• What level of access have they been granted?
• Could compromised supplier credentials provide access to other parts of your environment?
• What controls are in place to limit that access?

Core Question: What happens to your business if a supplier can’t operate?

This is one of the most frequently overlooked forms of third-party cyber risk.

A supplier may have no access to your network and none of your sensitive data. But if your organization depends on its product or service to operate, a cyberattack against that supplier can quickly become your problem.

Manufacturers provide an obvious example. Think about the materials and components required to keep a production line moving. If a critical supplier suddenly can’t produce or ship them, how long can your business continue operating?

What it can look like: Kojima Industries and Toyota

In 2022, Toyota supplier Kojima Industries experienced a suspected cyberattack that disrupted its ability to communicate with Toyota and manage production. The impact traveled downstream quickly.

Toyota suspended all 28 production lines across its 14 plants in Japan for a day.

Toyota wasn’t the company initially attacked, but Toyota experienced the business disruption.

That’s why evaluating third-party cyber risk requires organizations to look beyond their technology stack and ask:

• Which suppliers provide products or services that are essential to our operations?
• How long could we operate without them?
• Are alternative suppliers available?
• Which single-supplier dependencies could create significant disruption?

Sometimes the supplier posing significant cyber risk isn’t your largest technology vendor. It could be the company providing a relatively ordinary component your business can’t operate without.

Core question: Which suppliers can access your data — and which ones actually hold it?

Organizations routinely share information with outside partners.

Payroll providers may hold employee information. Benefits administrators process sensitive personal data. Accounting, legal and professional services firms may access confidential business information. SaaS providers can hold enormous amounts of company and customer data.

There are two important questions to consider:

Does the supplier have access to your data?

And:

Have you given the supplier your data to store or process within its environment?

Either relationship creates exposure. Your organization may have excellent internal cybersecurity controls, but once your information resides somewhere else, its security also depends on the organization protecting it.

What it can look like: Maximus, MOVEit and the State of Maryland

In 2023, attackers exploited a vulnerability in MOVEit, a file-transfer application used by Maximus, a third-party vendor for the State of Maryland’s Department of Human Services.

Maximus processed personally identifiable information belonging to Maryland residents and businesses. The attack resulted in the compromise of records belonging to approximately 5,000 individuals and 200 businesses, including information such as Social Security numbers, addresses and dates of birth.

The State of Maryland didn’t have to be directly breached for its information to be exposed.

That’s the third-party data problem: your data can be somewhere your security team doesn’t directly control.

To understand the risk in this box, consider:

• Which suppliers can access sensitive company, employee or customer data?
• Which suppliers store or process that information?
• What types of information have been shared?
• What would the business impact be if that information were exposed?

Core Question: Which third parties power experiences your customers associate with you?

The fourth box can be somewhat difficult to recognize.

Organizations increasingly rely on third parties to provide platforms, applications and services that become part of their own customer or user experience.

Sometimes those services are explicitly white-labeled and carry the organization’s brand. Other times the third-party provider is visible, but users still view the service as part of their relationship with your organization.

Either way, when the provider experiences a serious cyber incident, your organization may be left explaining the disruption to your customers, employees or other stakeholders.

What it can look like: The 2026 Canvas incident

Canvas provides a useful recent example.

Instructure operates Canvas, the learning management system used by thousands of schools and universities. In April 2026, Instructure detected unauthorized activity within Canvas. On May 7, the same threat actor gained additional access through another vulnerability and modified pages shown to some users. Instructure temporarily took Canvas offline while it contained the incident and applied additional safeguards.

The effects were immediately visible at customer institutions. Universities temporarily restricted access to their Canvas environments, while students, faculty and staff experienced disruption to a system they rely on for coursework and other academic activity. The University of Michigan, for example, temporarily restricted Canvas across all three campuses while it investigated and coordinated with Instructure.

Some institutional user information was also involved in the broader incident, including usernames, email addresses, course names, enrollment information and messages.

The lesson extends well beyond education.

If another company powers a product, portal, platform or service that your customers experience as part of doing business with you, its cyber risk can become your customer experience and reputational risk.

Ask:

• Which customer-facing services depend on third-party technology?
• Which products or services are white-labeled from another provider?
• If one of those providers went offline, what would our customers experience?
• Who would customers hold accountable for the disruption?

The Four Box methodology isn’t designed to place every supplier neatly into a single category.

In fact, the suppliers that deserve the greatest attention may appear in multiple boxes.

Consider a payroll provider. It might integrate with internal systems, provide an operationally important service and hold sensitive employee data.

Or an e-commerce provider that connects to internal systems, processes customer information and powers a customer-facing experience under your company’s brand.

The more ways a supplier can affect your organization, the more important it becomes to understand and manage the risk associated with that relationship.

The Four Box methodology also highlights why third-party cyber risk management shouldn’t belong exclusively to IT.

Your IT team knows which vendors connect to your systems.

But your head of supply chain may know which supplier could stop production.

HR knows which providers hold sensitive employee information.

Finance knows which partners are essential to financial operations.

Sales, operations and other business leaders may know which third parties are critical to serving customers.

Understanding third-party cyber risk requires bringing those perspectives together.

The question isn’t simply:

Which of our vendors could get hacked?

Any of them could.

The more useful question is:

If this supplier experienced a serious cyber incident tomorrow, how could it affect our business?

The Four Box methodology gives leaders a practical way to answer that question.

And once you understand how suppliers can introduce risk, the next challenge becomes determining which suppliers deserve the greatest attention — and what you should do about them.

That’s where an effective third-party cyber risk management program begins.