1. Introduction

In this tutorial, we’ll look into supply chain attacks. We’ll discuss what they are and how they usually work. After that, we’ll look at a real-world scenario where a supply chain attack was used and, finally, consider some countermeasures.

2. Supply Chain

Let’s start by giving a thorough definition of a supply chain. It’s a network of entities producing and handling goods or services from the supplier to the end customer. As an example, we’ll consider the supply chain for a piece of hardware inside our computers, a CPU:

Supply Chain example CPU

A CPU manufacturing supply chain may involve semiconductor suppliers providing raw materials like silicon components, fabrication facilities producing the chips, packaging and testing companies, logistics for component transportation, computer assembly plants integrating the CPUs into final products, and distributors delivering those products to consumers.

3. Supply Chain Attacks

A supply chain attack is a cyber-attack that targets vulnerabilities in any supply chain step.

In our example, one such attack could compromise a packaging and testing company. After infiltrating, the attackers tamper with the supply chain and alter the end product of the CPU with any means they have. For instance, attackers integrate hardware trojans into the design at this point. With this power, the attack aims to steal sensitive info or disrupt the operations of organizations at the end of the chain.

This attack is very similar to a watering hole attack in some ways. Both these processes aim to gain access to an organization without directly attacking its infrastructure. A watering hole attack targets websites users may visit, whereas a supply chain attack targets entities in the supply process until the end product.

4. Tactics and Techniques

These attacks often begin by compromising a seemingly unrelated but less secure element within the supply chain, such as a supplier or service provider. Once infiltrated, attackers can move laterally, gradually gaining access to more critical components until they reach the ultimate target.

4.1. Software Updates

Supply chain attacks encompass a variety of tactics, each tailored to exploit specific weaknesses within the interconnected network.

A standard method involves inserting malicious code into software updates. Adversaries target software vendors and inject malware into legitimate updates distributed to users.

This tactic can simultaneously compromise many systems, amplifying the attack’s impact and increasing detection chances.

4.2. Hardware Components

Another widespread strategy is compromising hardware components.

Attackers infiltrate the manufacturing process or the distribution chain, introducing compromised hardware into the supply chain. Then, the attackers embed these components into various devices, from routers to servers, gaining a lasting foothold on the systems.

4.3. Social Engineering

Phishing campaigns tailored to supply chain entities are also a common vector for these attacks. Attackers can trick employees into divulging sensitive information or downloading malicious payloads by impersonating trusted vendors or partners.

Threats also exist on the physical access level. Intercepting physical shipments and tampering with products during transit is a legitimate method of supply chain attack. Individuals with physical access at any point in the supply chain can also cause damage.

4.4. Categorization

We can categorize the attacks with respect to their techniques and targets:

Attack Type
Malicious Software Updates Malicious code is injected into software updates that reach the target organization. Software systems of vendors along the supply line.
Compromised Hardware Modifying or injecting extra parts inside hardware components The hardware manufactured inside the chain and delivered to the organization at the end of the chain.
Phishing Campaigns Phishing e-mails, impersonation of people inside the organization, etc. Any organization along the supply line.
Physical Access Tailgating, physically tampering with hardware, physical access to computing systems, etc. Any organization along the supply line.

5. Real-World Example

Over the years, several high-profile supply chain attacks have underscored the severity of this threat. One of the most infamous incidents was the SolarWinds supply chain attack, discovered in late 2020.

The SolarWinds attack was a sophisticated infiltration of the software supply chain with ripple effects resonating across the cybersecurity landscape even today. In this breach, the attackers targeted SolarWinds’ software development process by compromising the integrity of their Orion platform.

What set this attack apart was the calculated exploitation of trust inherent in supply chains: SolarWinds’ customers unwittingly received and implemented compromised software updates during routine maintenance. This strategy showcased how a single compromised link in the supply chain could be leveraged to compromise the security of more organizations, emphasizing the need for cybersecurity measures throughout the entire supply chain ecosystem.

6. Mitigation

Mitigating supply chain attacks involves proactively strengthening the network of suppliers, vendors, and service providers. The crucial first step is rigorous evaluation and management of vendors. This means thoroughly checking and continuously monitoring the cybersecurity practices of partners. Regular security checks, vulnerability assessments, and testing for potential weaknesses in the supply chain are essential.

Supply chain attacks pose a unique threat as they do not directly target an organization’s infrastructure. Therefore, collaboration and information sharing within the supply chain are vital for a strong defense. Establishing clear communication channels and sharing knowledge about potential threats can help all entities in the supply chain protect against emerging risks.

Diversifying the sources from which organizations get their supplies can reduce the impact of a possible compromise. If such an attack succeeds, relying 100% on the compromised entity can be catastrophic for everyone else further in the chain. In contrast, splitting the chain between multiple vendors means that even if one gets hacked, the rest of the supply chain will function as usual:

A distributed supply chain can mitigate some effects of a supply chain attack

As for specific technical pointers, we mention two countermeasures that are significantly effective against supply chain attacks:

  • Using secure coding practices, code signing, and thoroughly checking software and firmware updates. This can prevent the insertion of malicious code.
  • Adopting a zero-trust security model. Zero-trust is a cybersecurity model where no trust is inherently assumed, and both parties must verify every connection and communication.

7. Conclusion

In this article, we explained what a supply chain attack is. It doesn’t target an organization directly but the entities it relies on in a supply chain. The techniques employed in these attacks include inserting malicious code into software updates, compromising hardware components, phishing campaigns, or even threats on the physical level.

Mitigation is a difficult task. Each organization must strengthen and closely monitor the supply chain’s defense. Two things are crucial: communication between all parts of a supply chain and splitting supply between different vendors.

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