How third-party software introduces cyber risk for UK SMEs

Most UK SMEs rely on software they did not build themselves. That includes accounting platforms, customer relationship systems, payroll tools, booking systems, collaboration apps, and specialist industry products. This is normal and often sensible. Buying software is usually faster and cheaper than building everything in-house.

However, bought-in software changes your risk profile. You are no longer only relying on your own team to design, build, and maintain the system. You are also relying on the supplier’s security, their update process, their support model, and the security of the components they depend on. In practice, that means third-party software can introduce cyber risk even when your own staff have done nothing wrong.

The good news is that this risk can be managed. SMEs do not need a huge security function to make sensible decisions. A proportionate approach, focused on the software that matters most to the business, usually gives the best return.

What third-party software means in practice

Third-party software is any application, service, library, plugin, or platform that comes from outside your organisation. It may be installed on your own devices, hosted for you in the cloud, or embedded inside another product you use.

Examples of third-party software in a typical SME stack

For many SMEs, this includes finance systems, HR platforms, email and collaboration tools, customer portals, website plugins, payment services, remote support tools, and software used by suppliers to connect into your environment. It can also include open-source components that your own developers use inside a product or internal system.

Some of these tools are business-critical. Others are convenient but not essential. The difference matters because the more important the software is to your operations, the more carefully you should assess and monitor it.

Why bought-in software changes your risk profile

When you buy software, you inherit a set of assumptions. You assume the supplier patches quickly, protects customer data properly, and manages their own dependencies well. You also assume the software will keep working as expected, and that any changes will be communicated in time for you to respond.

Those assumptions are not always wrong, but they should be checked. A product can look reliable on the surface while still carrying hidden risk through weak maintenance, poor access controls, or outdated components.

Where cyber risk enters through third-party software

Third-party software introduces risk in several ways. The most common are vulnerabilities in the software itself, weaknesses in the components it depends on, and poor supplier security practices.

Vulnerabilities in the application itself

Like any software, third-party applications can contain flaws. These may allow unauthorised access, data leakage, or service disruption. The issue is not that software has bugs, because all software does. The issue is how quickly those bugs are found, fixed, and communicated.

If a supplier is slow to patch, or if customers are not told clearly what to do, the window of exposure can stay open longer than it should. For an SME, that can be difficult to manage if the product is central to daily operations.

Dependencies, plugins, and transitive components

Modern software rarely stands alone. It often depends on other software components, such as open-source libraries, frameworks, plugins, and services. These are sometimes called dependencies. A transitive dependency is a component used by one of your dependencies, which means the chain can go several layers deep.

This matters because a weakness in one small component can affect the main product you rely on. You may never see that component directly, but it can still create risk. This is one reason why software supply chain security has become such an important topic.

Plugins deserve special attention. They often extend a product’s functionality, but they can also increase the attack surface if they are poorly maintained or granted too much access.

Weak supplier security practices and poor maintenance

Sometimes the risk is not the software itself, but the way it is run. A supplier may have weak internal controls, poor access management, limited monitoring, or an unclear patching process. They may also stop supporting older versions while customers continue to use them.

For SMEs, this can create a false sense of security. A product may be familiar and widely used, but if the supplier is not maintaining it properly, the business risk can rise quietly over time.

Common business impacts for UK SMEs

The impact of third-party software risk is usually practical rather than dramatic. It shows up as downtime, data issues, unexpected cost, or extra work for internal teams.

Service disruption and operational downtime

If a supplier has an outage, a security issue, or a delayed patch, your own operations may be affected. That can mean lost sales, missed deadlines, delayed customer service, or manual workarounds that slow the business down.

For SMEs, even short disruption can be painful because teams are small and processes are often tightly coupled to a few key systems.

Data exposure and integrity issues

Third-party software often stores or processes business data. That may include customer records, employee information, financial data, or confidential commercial information. If the software is compromised, data may be exposed, altered, or deleted.

Integrity matters as much as confidentiality. If records are changed without authorisation, the business may make decisions based on inaccurate information. That can be harder to spot than a clear outage.

Unexpected cost from urgent fixes and contract changes

When a supplier issue becomes urgent, the cost is rarely limited to the supplier’s fee. You may need internal staff time, external support, emergency testing, temporary workarounds, or contract changes. In some cases, you may also need to replace the product entirely.

That is why software risk should be treated as a business issue, not just a technical one. The cheapest product is not always the lowest-risk option once support, maintenance, and exit costs are included.

How to assess third-party software before you buy or renew

A sensible review before purchase or renewal can prevent a lot of trouble later. The aim is not to demand perfection. It is to understand whether the software is suitable for your business, and whether the supplier can support it responsibly.

Questions to ask suppliers about security and support

Start with straightforward questions. Ask how the product is secured, how often it is updated, how vulnerabilities are handled, and how long the supplier will support the version you plan to use. Ask whether the supplier uses subcontractors or external hosting providers, and whether those arrangements affect your data or service availability.

You should also ask who is responsible for security incidents, how the supplier notifies customers about urgent issues, and what support is available if something goes wrong. Clear answers are usually a good sign. Vague answers are a warning that the supplier may not have thought this through properly.

What to look for in update, patching, and disclosure processes

Look for a predictable patching process, a clear support lifecycle, and a way to disclose vulnerabilities responsibly. You do not need a long technical explanation, but you do need confidence that issues will be handled in a timely way.

It is also worth checking whether the supplier publishes release notes, whether updates are automatic or manual, and whether changes can be tested before rollout. For business-critical software, that can make the difference between a controlled change and a disruptive one.

How to reduce risk after deployment

Buying the software is only the start. Once it is in use, you still need to configure it well, keep track of updates, and review the supplier relationship over time.

Limit access and configure software securely

Apply the principle of least privilege, which means giving users only the access they need to do their job. Remove unused accounts, review administrator rights, and make sure multi-factor authentication is enabled where available.

Check default settings carefully. Many products are designed for convenience, not security. Features such as public sharing, broad integrations, or permissive guest access may be useful, but they should be enabled deliberately rather than left on by default.

Track versions, updates, and end-of-life dates

Keep a simple record of what software you use, which version is in place, and when support ends. End-of-life means the supplier no longer provides security fixes or meaningful support. Continuing to use unsupported software increases risk because known issues may remain unpatched.

This does not need to be a complex process. A basic asset register, linked to the supplier record, is often enough for an SME to stay on top of the most important products.

Review critical suppliers on a regular basis

Do not treat supplier review as a one-off exercise. Revisit critical software at a sensible interval, especially if the product handles sensitive data or supports core operations. Check whether the supplier has changed hosting arrangements, support terms, ownership, or update practices.

A short annual review is often enough for lower-risk tools. Higher-risk systems may need more frequent attention, particularly if they are internet-facing or deeply integrated with other services.

How to build third-party software risk into everyday governance

Third-party software risk becomes easier to manage when it is part of normal governance rather than a separate project. The aim is to make the process repeatable and proportionate.

Link software risk to asset and supplier registers

If you already keep an asset register or supplier list, add software risk information to it. Note which systems are business-critical, what data they handle, who owns them internally, and when the supplier support ends. This gives decision-makers a clearer picture of where attention is needed.

It also helps when staff change roles or leave. Ownership is easier to maintain when it is written down rather than kept in someone’s head.

Use proportionate review based on business impact

Not every application needs the same level of scrutiny. A low-risk newsletter tool does not need the same review as a payroll platform or customer portal. Focus your effort where the business impact would be highest if the software failed or was compromised.

That approach keeps the process practical. It also helps avoid overcomplicating procurement with controls that add little value.

A practical checklist for SME decision-makers

If you want a simple starting point, use the following checklist when assessing or reviewing third-party software.

Prioritise the software that matters most

Identify the systems that support revenue, customer service, payroll, finance, and sensitive data. These are usually the products where supplier weakness would hurt most.

For each one, ask: what happens if it fails, who depends on it, and how quickly could we recover?

Assign owners for review, patching, and supplier contact

Make sure someone is responsible for each key product. That person does not need to be a technical specialist, but they should know when to escalate issues, who to contact at the supplier, and how to track updates or support notices.

Without ownership, even good controls tend to drift.

For many SMEs, the right answer is not to avoid third-party software. It is to buy carefully, configure it properly, and keep a light but consistent grip on the suppliers that matter most.

If you would like help reviewing your software suppliers, setting a proportionate assurance process, or linking third-party software risk into your wider information security governance, speak to a consultant.

Frequently asked questions

How is third-party software different from software we build ourselves?

Software you build yourself is under your direct control, so you can decide how it is designed, tested, deployed, and maintained. Third-party software depends on the supplier’s choices as well as your own. That means you need to consider not just how you use the product, but how the supplier supports it and how quickly they respond to issues.

What should an SME ask a supplier before adopting their software?

Ask about security updates, support life, vulnerability handling, data hosting, subcontractors, access controls, and incident notification. You should also ask what happens if the supplier changes ownership, discontinues the product, or needs to make urgent changes. The aim is to understand whether the product is sustainable and supportable for your business, not just whether it looks suitable on day one.

Third-party software can be a strong enabler for SMEs, but only when the associated risk is understood and managed in a practical way. A small amount of structure at the start usually saves time, cost, and disruption later.

The post How third-party software introduces cyber risk for UK SMEs appeared first on Clear Path Security Ltd.

*** This is a Security Bloggers Network syndicated blog from Clear Path Security Ltd authored by Clear Path Security Ltd. Read the original post at: https://clearpathsecurity.co.uk/how-third-party-software-introduces-cyber-risk-for-uk-smes/