Supply Chain Attacks: The Invisible Threat in Your Vendor Network

Picture this: your IT security is solid. Firewalls are running, employees are trained, and your systems are patched. Yet you get breached — not through your own network, but through the accounting software of a vendor you've trusted for years. This isn't a hypothetical scenario. This is how supply chain attacks work, and they're among the fastest-growing cyber threats today.

What Is a Supply Chain Attack?

In a supply chain attack, the attacker doesn't target your organisation directly. Instead, they compromise a link in your supply chain — a software vendor, an IT service provider, a cloud platform, or even a hardware manufacturer. By compromising one supplier, the attacker gains access to all of that supplier's customers, sometimes thousands of organisations at once.

The infamous SolarWinds attack of 2020 illustrates this perfectly. Attackers infiltrated SolarWinds' build system and injected malware into a legitimate software update. More than 18,000 organisations — including government agencies and Fortune 500 companies — installed the compromised update in good faith.

Why Supply Chain Attacks Are So Effective

The Trust Principle

The core of the problem is psychological. Organisations build trust relationships with their vendors. Software updates are installed automatically, suppliers are granted access to internal systems, and nobody questions whether the accounting application that's been running smoothly for five years suddenly contains malicious code.

This is precisely the behavioural pattern that Nexus-7 focuses on with the Q-Method: identifying unconscious assumptions and blind spots in how employees and organisations handle trust and risk. Supply chain attacks don't exploit a technical vulnerability — they exploit human trust.

The Scale Advantage for Attackers

From a cybercriminal's perspective, a supply chain attack is remarkably efficient. Instead of attacking a thousand organisations individually, you compromise one supplier and reach all those organisations through a trusted channel. The investment is high, but the return is enormous.

The Detection Challenge

Because the malicious code arrives through a trusted source — an official software update, a certified component — it bypasses most security measures. Traditional endpoint protection doesn't flag the malware because it runs within a legitimate process.

The Different Forms of Supply Chain Attacks

Software Supply Chain

The most common variant. Attackers compromise the development or distribution process of software. This can happen through:

• Compromised updates: Malware is inserted into legitimate software updates
• Dependency attacks: Malicious code is added to open-source libraries that thousands of applications depend on
• Code signing compromises: Attackers steal the certificates used to sign software

The recent XZ Utils backdoor incident (2024) demonstrated how an attacker spent years building trust within an open-source community, ultimately inserting a backdoor into a widely-used compression library.

Managed Service Provider (MSP) Attacks

IT service providers often have deep access to their clients' systems. A compromised MSP is like a key that fits hundreds of doors. The 2021 Kaseya attack hit more than 1,500 organisations worldwide through a single MSP platform.

Hardware Supply Chain

Less frequent but potentially devastating: manipulated hardware components or firmware that are already compromised upon delivery.

What NIS2 Requires for Supply Chain Security

The NIS2 directive, being implemented across the EU, explicitly addresses supply chain risks. Article 21 requires organisations to:

• Assess and manage risks in the supply chain
• Include security aspects in contracts with direct suppliers and service providers
• Account for vulnerabilities specific to each direct supplier
• Evaluate the overall quality of products and cybersecurity practices of suppliers

This means supply chain security is no longer optional — it's a legal obligation.

Practical Steps to Secure Your Supply Chain

1. Map Your Supply Chain

You can't protect what you don't know. Create a complete inventory of all vendors that have access to your systems, process your data, or supply software you use. Classify them based on the risk they pose.

2. Set Security Requirements for Vendors

Include concrete cybersecurity requirements in your contracts. Consider:

• Mandatory security certifications (ISO 27001, SOC 2)
• Incident notification obligations
• Right to audit
• Minimum security standards for access to your systems

3. Implement Zero Trust Principles

Don't blindly trust any connection, even from known vendors. Limit access rights to the strictly necessary, monitor all activity, and verify continuously.

4. Monitor Continuously

Periodic assessments aren't enough. Implement continuous monitoring of vendor risks. This includes tracking security incidents at vendors, monitoring access patterns, and regularly re-evaluating risk classifications.

5. Prepare an Incident Response Plan

What do you do when a vendor turns out to be compromised? Ensure your incident response plan includes specific scenarios for supply chain incidents, including communication procedures and isolation measures.

The Human Factor: Where Technology Falls Short

Supply chain security is ultimately a people problem. It comes down to the decisions employees make every day: which software they install, which vendors they trust, how they handle updates and access requests.

That's why a behaviour-focused approach to cybersecurity is essential. Nexus-7's Q-Method maps how your organisation handles trust, risk assessment, and decision-making around vendors. Not by ticking off a checklist, but by making actual behaviour and underlying assumptions visible.

Conclusion

Supply chain attacks aren't a future scenario — they're happening now, growing more sophisticated, and hitting organisations of every size. The combination of NIS2 obligations and the evolving threat landscape makes supply chain security a top priority for every organisation.

The question isn't whether your supply chain is a target, but whether you're prepared when it happens.

Frequently Asked Questions

Are supply chain attacks only relevant for large organisations?
Absolutely not. SMEs are particularly vulnerable because smaller suppliers often have weaker security while still maintaining deep access to their clients' systems.

How do I know if my vendors are secure?
By actively setting security requirements, verifying certifications, and conducting regular risk assessments. A one-time check at contract signing is insufficient.

What's the difference between a supply chain attack and a regular hack?
In a regular hack, your organisation is the direct target. In a supply chain attack, you're indirectly affected through a compromised vendor or service provider.