Supply Chain Security Testing: Testing Third-Party Risk Exposure for Proactive Supply Chain Security

In May 2023, a ransomware gang known as CL0P exploited a zero-day vulnerability in Progress Software’s MOVEit managed file transfer application. The breach allowed the attackers to steal large amounts of sensitive data from millions of individuals, leaving them susceptible to identity theft, fraud, and other problems. This attack affected over 2,500 organizations.¹ Many of these corporate victims lost large volumes of confidential data, suffered financial damage, or found themselves facing regulatory investigations, fines, and even class-action lawsuits.

The MOVEit breach is a textbook example of the fallout that supply chain attacks can cause on the extreme end of the spectrum.

At the foundational level, supply chain attacks are the result of weaknesses in a firm’s software supply chain. Adversaries target the intricate relationship networks between organizations and their third-party software vendors, exploiting vulnerabilities in organizations’ third-party software products to reach their primary target or even multiple organizations. As we’ve seen with the MOVEit breach, these attacks can have wide-ranging and long-term negative effects on all users of that product.

So how can your organization withstand supply chain attacks? Through supply chain security testing and vendor assessments.

Continuous third-party risk assessments and vendor assessments performed by reliable external certified ethical hackers and pentesters can minimize your exposure to third-party risk and reduce the probability of supply chain attacks by ensuring that your third-party providers remain a source of business strength rather than a source of business risk.

Identifying and Addressing Third-party Risk Exposure with Supply Chain Security Testing

As organizations embrace digital transformation, their software supply chains are growing more intricate and more vulnerable. Every new integration, vendor, or SaaS connection adds another potential entry point for attackers.

The World Economic Forum’s 2024 Global Cybersecurity Outlook found that over half of large enterprises cite third-party software vulnerabilities as their biggest barrier to cyber-resilience.² Those fears are well-founded, as according to the 2025 Verizon DBIR, nearly one-third of all breaches last year involved a third party, double the rate of 2023.³

These trends reinforce the simple truth that you can’t defend what you can’t see, making visibility into the software supply chain a survival requirement.

That’s where supply chain security testing comes in.

Rather than waiting for a downstream vendor breach to cause undue harm to your business, supply chain security testing enables you to proactively uncover weak links and hold software vendors accountable for ensuring their products are secure. Through targeted third-party risk assessments and continuous vendor validation, security teams should gain:

• Real-time insight into vulnerabilities existing within vendor systems
• Assurance that third-party controls align with compliance obligations
• Confidence that every partner or link in the software supply chain is a security ally, vs. a liability

This proactive approach transforms supply chain security from a reactive scramble into a strategic, ongoing practice that strengthens resilience, supports compliance, and protects your organization’s reputation.

Vendor Assessments and Penetration Testing: The Two Key Pillars of Supply Chain Security Testing

Supply chain security testing isn’t a one-time audit, but rather a continuous validation process that ensures your third-party ecosystem remains secure in the face of emerging threats as it evolves. It encompasses continuous vendor assessments, ongoing vendor security validation, and periodic pentesting of vendor systems.

Vendor assessments typically evaluate the security posture of third parties before and after onboarding. The goal is to map who has access to your systems and data, assess how that access is managed, and confirm whether vendors meet your internal and regulatory security requirements (e.g., GDPR, HIPAA, PCI DSS, SOC 2).

Penetration testing goes beyond paperwork and policy, testing your vendors’ defenses in practice. The goal is to identify exploitable weaknesses, misconfigurations, or inherited risks that traditional audits often miss. Together, these practices offer a clear, evidence-backed view of how secure your supply chain truly is.

Overall, supply chain security assessments and validations typically include all the following activities:

• Identifying all the third parties that might have access to your systems or data
• Determining what kind of data they can access or process
• Listing their access levels, permissions, and privileges
• Assessing their current security measures and third-party risk management practices
• Identifying and evaluating the vulnerabilities in their systems that can potentially impact your systems or data
• Monitoring vendors for incidents and threats in real-time
• Assessing third parties’ security postures and monitoring any changes
• Comparing whether vendor systems and controls comply with relevant regulatory frameworks (GDPR, HIPAA, PCI DSS, SOC 1, SOC 2, and so on)

Challenges of Supply Chain Security Testing

Even the most mature organizations encounter challenges with the complexity of supply chain security testing. The process is time-consuming, requires technical and regulatory expertise, and demands constant vigilance. Understanding the evolving threat landscape, tracking vendor security controls, and staying current with shifting compliance frameworks (like SOC 2, HIPAA, or PCI DSS) is not an easy feat for internal teams with limited resources and bandwidth.

That’s why many organizations partner with external experts to extend their capabilities and accelerate third-party risk validation. A trusted testing partner can help provide on-demand access to expert-led penetration testing. Many of these pentesting service providers bring specialized expertise in software supply chain ecosystems, regulatory requirements like PCI DSS, SOC 2, HIPAA, etc., and emerging threats, and some even offer complimentary solutions to broaden and deepen coverage, such as attack surface management (ASM) for identifying new exposures, and adversarial exposure validation (AEV) for autonomous red teaming.

By leveraging an external supply chain security testing partner, you can:

• Verify that vendor systems and applications are secure and resilient against attack.
• Establish standardized, repeatable processes for uncovering vulnerabilities across vendors.
• Gain deep visibility into the security posture of partners, suppliers, and SaaS providers.
• Protect sensitive data and intellectual property from cascading supply chain breaches.
• Identify and remediate third-party risks before they lead to business or reputational damage.
• Demonstrate compliance with stringent data protection and regulatory requirements.

Ultimately, outsourcing supply chain security testing allows your team to focus on strategic defense while ensuring every link in your vendor ecosystem remains trusted, tested, and secure.

Strengthen Supply Chain Resilience with BreachLock

Modern supply chains often fail because unseen exposures connect across dozens of dependencies. BreachLock helps you proactively uncover, validate, prioritize, and mitigate those hidden risks before adversaries do.

The BreachLock Unified Platform brings together Penetration Testing as a Service (PTaaS), Adversarial Exposure Validation (AEV), and Attack Surface Management (ASM) to deliver continuous, evidence-based assurance across your entire digital ecosystem.

Penetration Testing as a Service (PTaaS)

With BreachLock PTaaS, you can scale your pentesting initiatives with human-led, AI-powered, and automated pentesting on demand across your applications, networks, APIs, cloud environments, AI assets, and more. Every test is led by certified experts and AI-accelerated validation that accelerates evidence gathering, reporting, and remediation guidance, cutting testing costs and timelines by up to 50%.

Adversarial Exposure Validation (AEV)

BreachLock AEV is a generative AI-powered autonomous red teaming engine that helps users emulate attacker behavior across your attack surface to demonstrate how exposures can be chained and exploited in real-world scenarios. Being able to visualize attack chains in real-world scenarios helps you prioritize fixes that actually reduce business risk and allocate resources where they have the most impact.

Attack Surface Management (ASM)

BreachLock ASM continuously discovers and monitors your external-facing assets, giving you full visibility into what attackers can see. By mapping new and evolving exposures to your attack surface in real time, ASM helps you stay ahead of risks introduced by your supply chain and partner integrations.

Together, these capabilities can help truly transform your third-party and supply chain risk management program from reactive to proactive with unified visibility, validated findings, and clear guidance on where to focus remediation efforts for the biggest impact.

Learn how BreachLock can help you continuously discover and validate exposures and reduce third-party risk. Schedule a discovery call today!

References

1. Cyber Magazine (November 2024). Amazon: How MOVEit Supply Chain Attack Left Echoing Effects. https://cybermagazine.com/articles/amazon-how-moveit-supply-chain-attack-left-lasting-effects

2. World Economic Forum. (January 2025). Global Cybersecurity Outlook 2025. https://www.weforum.org/publications/global-cybersecurity-outlook-2025/digest/

3. Verizon (2025). 2025 Data Breach Investigations Report. https://www.verizon.com/business/resources/Tb68/reports/2025-dbir-data-breach-investigations-report.pdf

Author

BreachLock Labs