The weakest link isn't in your network — it's in your supplier's
Picture this: your IT security is airtight. Firewalls configured to spec, staff trained and vigilant, patches applied on schedule. Yet you get breached. Not through your own systems, but through your accounting software vendor who was three months behind on updates.
This isn't hypothetical. It mirrors real attacks on major European organisations in recent years, and the pattern is accelerating. Supply chain attacks — cyber attacks that reach you through your vendors and service providers — rank among the fastest-growing threats today. The European Union Agency for Cybersecurity (ENISA) reports a 300% increase in supply chain incidents since 2021.
What exactly is a supply chain attack?
In a supply chain attack, the attacker doesn't target the final victim directly. Instead, they compromise a supplier, software vendor, or service provider that has access to the target's systems or data. Common vectors include:
- Software vendors pushing updates laced with hidden malware (as in the infamous SolarWinds breach)
- Managed service providers (MSPs) whose administrative access is hijacked to hit dozens of clients at once
- Cloud providers where a vulnerability in shared infrastructure exposes multiple organisations
- Hardware suppliers where components are tampered with before delivery
The insidious part: you have limited visibility into what happens inside your supplier's walls. You trust their security — but have you ever verified whether it meets your standards?
Why supply chain attacks work so well
Three psychological and organisational factors make this attack method devastatingly effective:
1. Trust as a weapon
People and systems trust their suppliers. Software updates install automatically. Data flows through established integrations. Attackers exploit exactly this trust. You might hesitate before clicking a suspicious email, but you won't think twice about an update from your regular software vendor.
2. Scale advantage for the attacker
A single successful attack on one supplier can compromise thousands of organisations simultaneously. For cybercriminals, this is the most efficient path to maximum damage — or maximum ransom.
3. Limited risk visibility
Most organisations lack a complete picture of their digital supply chain. Who has access to your systems? What software runs on which servers? What API integrations exist? Without that overview, you cannot manage the risk.
NIS2 mandates supply chain security
The European NIS2 Directive, being transposed into national law across EU member states, explicitly addresses supply chain security. Organisations within scope must:
- Identify and manage risks in their supply chain
- Establish contractual security requirements with suppliers
- Report supply chain incidents to competent authorities
- Periodically assess the cybersecurity maturity of their suppliers
These aren't optional recommendations — they are legal obligations carrying significant fines for non-compliance. Board members can be held personally liable.
Five practical steps to secure your supply chain
1. Map your digital chain
Create a comprehensive inventory of all suppliers, software products, cloud services, and API integrations with access to your systems or data. Many organisations discover connections they didn't know existed during this exercise.
2. Classify suppliers by risk
Not every supplier carries the same risk. A vendor with direct network access is far more critical than one supplying office stationery. Prioritise your security efforts based on potential impact.
3. Set contractual security requirements
Include cybersecurity obligations in your procurement contracts. Think mandatory ISO 27001 certification, periodic penetration testing, incident notification duties, and audit rights.
4. Monitor continuously
A supplier that's secure today could be compromised tomorrow. Implement continuous supplier monitoring — not just an annual checklist, but active signal detection across your vendor ecosystem.
5. Rehearse your response
What do you do when a supplier gets breached? How do you isolate the connection? Who do you notify? Include supply chain scenarios in your incident response exercises.
The human factor: it runs through the chain too
At Nexus-7, we consistently find that technical controls alone fall short. Our Q-Method behavioural analysis reveals the same pattern time and again: the greatest vulnerabilities stem from human behaviour. An employee at your supplier clicking a phishing link. A system administrator who never changes default credentials. A manager who dismisses security warnings because they "slow things down."
Supply chain security therefore demands more than technical controls — it requires insight into the security awareness and behaviour across your entire chain. How do your suppliers' employees handle sensitive information? Are they trained? Is that training tested?
From risk to resilience
Supply chain attacks aren't a problem you solve alone. They require collaboration with your suppliers, clear agreements, and mutual trust — but trust built on evidence, not assumptions.
The organisations that handle this best treat supply chain security not as a compliance checkbox, but as a strategic component of their risk management. They invest in visibility, set boundaries on access, and build a culture where security is a shared responsibility.
Want to know where your organisation stands? A supply chain security assessment gives you concrete insight into the risks entering through your suppliers — and what you can do about them.
