How to Assess the Cyber Security of Your Vendors

Your cyber security is only as strong as the weakest link in your supply chain. Every supplier, software provider, and service partner that connects to your business data or systems introduces a potential vulnerability — one that's often outside your direct control.

This isn't a theoretical risk. Some of Australia's most significant data breaches in recent years have originated not with the breached organisation itself, but with a third-party vendor. Understanding and managing vendor security risk is one of the most important — and most overlooked — aspects of small business cyber security.

Why Vendor Risk Matters for Small Businesses

Think about the businesses and software you rely on daily. Your accounting software. Your payroll provider. Your website developer. Your cloud storage service. Your managed IT provider. Each of these holds or can access your business data, and each represents a potential attack vector.

Attackers know that targeting a well-resourced enterprise directly is difficult. Targeting one of their smaller, less-secured suppliers — and using that access to pivot into the larger organisation — is often much easier. Small businesses are frequently caught in the middle of these supply chain attacks even when they're not the ultimate target.

The Australian Signals Directorate's Annual Cyber Threat Report consistently identifies supply chain compromise as a growing threat vector for Australian businesses of all sizes.

Start by Mapping Your Vendors

Before you can assess vendor risk, you need to know who your vendors are. Create a simple spreadsheet listing:

• Every software tool and cloud service your business uses
• Every external service provider with access to your systems or data
• What data or access each vendor has
• Whether the relationship is critical to your operations

You might be surprised how long this list gets. Many small businesses have 20 to 40 SaaS tools and service providers with some level of access to their business data, even if they've never thought of them as "vendors" in a formal sense.

Prioritise by Risk Level

Not every vendor deserves the same level of scrutiny. Prioritise your assessment based on two factors: what access the vendor has and how critical they are to your operations.

Vendors in the high-priority category include those that:

• Store or process sensitive customer data (names, financial information, health records)
• Have direct access to your core systems (accounting, payroll, CRM)
• Could disrupt your operations significantly if they were unavailable or compromised
• Have remote access to your network or devices

Lower-priority vendors are those you use for non-sensitive, non-critical tasks — for example, a graphic design tool that doesn't hold customer data and isn't integrated with your core systems.

What to Ask Your High-Priority Vendors

For vendors in the high-priority category, it's worth asking some direct questions about their security practices. You can do this via email, a phone call, or by requesting their security documentation. Key questions include:

Data Security

• Is our data encrypted at rest and in transit?
• Where is our data stored? (Australian data residency may be relevant for some industries)
• Who within your organisation can access our data?
• Do you use sub-processors or share our data with other third parties?

Access Controls

• Do you use multi-factor authentication for staff who access customer data?
• How do you manage and review privileged access?

Incident Response

• Do you have a documented incident response plan?
• How would you notify us if our data was involved in a breach?
• What is your typical notification timeframe after a breach is discovered?

Certifications and Assessments

• Do you hold any relevant security certifications? (ISO 27001, SOC 2 Type II, and the Australian Government's Essential Eight alignment are worth asking about)
• Have you undergone any independent security assessments in the past 12 months?

Use Publicly Available Information

You don't have to rely solely on what vendors tell you about themselves. For larger software providers, look for:

• Published SOC 2 reports or ISO 27001 certificates (many cloud providers make these available on request or in their trust portals)
• Trust and transparency pages — Salesforce, Atlassian, Xero, MYOB, and most major SaaS providers publish security documentation here
• Recent news articles about security incidents involving the vendor
• The vendor's privacy policy and terms of service, which describe how your data is handled

Evaluate Their Response

How a vendor responds to your security questions is itself informative. A vendor that responds promptly with clear, specific answers is demonstrating that security is taken seriously. A vendor that is vague, dismissive, or unresponsive to legitimate security questions is a risk indicator.

For critical vendors, a poor response to security questions should prompt you to reconsider the relationship or at minimum to apply additional controls on your end, such as limiting the data you share with them.

Build Vendor Security into Your Procurement Process

Rather than assessing vendors reactively, build security questions into your process for choosing any new vendor. Before signing up for a new tool or engaging a new service provider, add a simple security checklist to your evaluation process. It takes a few minutes and can save significant headaches later.

Key Takeaways

• Map all your vendors and identify which ones have access to sensitive data or critical systems
• Prioritise security assessments for high-risk vendors — those with direct access to your data or systems
• Ask vendors specific questions about data security, access controls, incident response, and certifications
• Use publicly available trust documentation and SOC 2 reports to supplement what vendors tell you
• Build vendor security checks into your standard procurement process for all new tools and services

Understanding your vendor risk is a critical part of understanding your overall cyber risk. Take the free Flagged assessment to see how your supply chain security compares and get specific recommendations for your business.