The rise of digital supply chains forces companies to pay close attention to their suppliers’ cybersecurity. Threats do not stop at your internal perimeter. Relationships with third parties, partners and subcontractors can carry unexpected risks if not properly managed. This article walks you through the steps of an effective audit and the best practices to secure your organisation against external risks.
What is a supplier cybersecurity audit?
A supplier cybersecurity audit evaluates the security level of your external partners’ systems and practices. It checks whether their security policies meet current standards and regulations such as GDPR, ISO 27001, as well as newer regulations like DORA (Digital Operational Resilience Act) and NIS 2 (Network and Information Security Directive 2). These regulatory frameworks aim to strengthen the digital resilience of companies and their ecosystems by requiring solid information-system and third-party security.
Why is this so critical? Because a poorly secured supplier can become an entry point for cyberattacks, such as ransomware, that can compromise your own systems. An audit lets you identify vulnerabilities in their infrastructure and take the actions needed to strengthen data protection.
Why a supplier cybersecurity audit is essential for your company
Identifying third-party risks
Suppliers can have access to critical information or essential systems. Without a rigorous review of their security posture, you risk exposing your own infrastructure to attacks. An audit surfaces:
- Security gaps inside suppliers’ systems.
- Poor data-protection practices.
- Level of compliance with regulations (GDPR, DORA, NIS 2, etc.).
Strengthening trust with partners
Auditing partners regularly builds mutual trust. When suppliers demonstrate their cybersecurity maturity, they actively contribute to securing your own environment. This creates a relationship built on transparency and security — a significant competitive edge in many industries.
Reducing cybersecurity-incident costs
Regular audits reduce the potential costs tied to a cyberattack coming from a vulnerable supplier. Incidents such as data breaches or intrusions into critical systems can cost millions of euros, not counting reputational damage. Anticipating these risks limits the financial impact.
How to run an effective supplier cybersecurity audit
Step 1 — Risk assessment
The first step is to evaluate the inherent risk of each supplier. Not all third parties carry the same threat level. A supplier with access to critical data or production systems is higher-risk than a pure service provider unrelated to your core business. The goal is to prioritise suppliers based on criticality. Key criteria include:
- Supplier company size: large companies may have dedicated cybersecurity teams; smaller ones may lack the resources to deliver strong security.
- Connection level with your internal systems: a supplier with access to your network or critical systems represents increased risk. You need to understand the breadth of connections between your infrastructure and theirs.
- Security track record: a supplier that recently experienced a data breach or cyberattack deserves a deeper review. It helps surface weaknesses in their security practices.
Risk assessment must include an analysis of each supplier’s cyber maturity — their ability to respond to threats and comply with regulations (GDPR, DORA, NIS 2, ISO 27001). A thorough evaluation lets you classify suppliers by risk level and organise audits accordingly.
Step 2 — Analyse security processes and systems
Once high-risk suppliers are identified, run a detailed analysis of their security processes and systems. This covers reviewing their Information Security Policy (ISP) and the specific measures they put in place to protect data. Key items to check:
- Security policies: does the supplier have written policies covering critical areas such as access management, sensitive-data protection, network security and cyberattack prevention?
- Employee training: are the supplier’s employees trained on cybersecurity best practices? Human error is a leading cause of security incidents.
- Data protection: make sure the supplier complies with data-protection regulations such as GDPR. This includes encryption and access-rights management.
- Compliance with standards: does the supplier follow good security practices such as those defined by ISO 27001, NIST, or the specific requirements of DORA and NIS 2?
This analysis lets you determine whether the supplier’s security practices match your organisation’s expectations and regulatory requirements.
Step 3 — Penetration tests and technical assessment
To evaluate how robust suppliers’ infrastructure and systems are against cyberthreats, penetration testing is essential. These tests simulate an attack and surface potential vulnerabilities that cybercriminals could exploit. There are several types of penetration tests:
- Black-box tests: the auditor has no prior information about the system. This simulates an external attack with no access to the supplier’s internal information.
- Grey-box tests: the auditor has partial knowledge of the systems. This tests more realistic scenarios where an attacker might have some internal information.
- White-box tests: the auditor has full information about the system. Used to examine the architecture and security systems in depth.
Depending on the chosen test type, the auditor looks for flaws in networks, applications or access systems. A network penetration test might reveal vulnerabilities in firewalls or poorly secured network configurations. An application test could identify weaknesses in the applications used by the supplier, such as source-code vulnerabilities.
These tests assess systems’ resistance to real attacks and recommend ways to strengthen security.
Step 4 — Continuous monitoring
An audit cannot be a one-off — risks evolve constantly. To guarantee an optimal security level, continuous monitoring is essential. That means using monitoring and risk management tools to track suppliers’ security practices in real time.
Good practices to ensure continuous monitoring:
- Deploy automatic monitoring tools: SaaS risk-management solutions let you continuously monitor supplier cybersecurity performance. They provide real-time visibility on potential vulnerabilities.
- Follow up on corrective actions: if the audit reveals gaps, make sure the supplier carries out corrective actions. Continuous monitoring lets you track these actions and verify they have been properly applied.
- Refresh audits regularly: cybersecurity is constantly evolving. Reassess suppliers regularly based on new threats and regulatory changes. Audit frequency depends on risk level and service type.
With continuous monitoring, potential vulnerabilities are detected and fixed quickly, keeping your organisation safe against third-party risks.
Best practices for auditing suppliers effectively
Define clear, standardised audit criteria
For a cybersecurity audit to be effective, you need to define standardised evaluation criteria based on recognised frameworks. Using frameworks such as ISO 27001, NIST or ANSSI recommendations (France’s national cybersecurity agency) lets you structure the audit around proven best practices. Key areas to cover:
- Identity and access management: suppliers must have rigorous controls over who accesses what inside their systems.
- Data protection: the supplier must demonstrate its ability to secure sensitive data, use encryption and manage access to critical information.
- Threat monitoring and detection: the audit must verify that the supplier has monitoring solutions capable of quickly detecting any suspicious activity.
- Regulatory compliance: make sure the supplier complies with applicable regulations (GDPR, DORA, NIS 2) and follows cybersecurity best practices.
Strengthen collaboration with your suppliers
A cybersecurity audit should not be seen as a simple external inspection but as active collaboration with your partners to improve security across the supply chain. Some practices that help build effective collaboration:
- Create a shared cybersecurity charter: this charter clearly defines each party’s responsibilities for protecting systems and data.
- Encourage transparency: invite suppliers to regularly share their security practices and inform you of any incident or risk detected.
- Train suppliers: in some cases, running training sessions can help them improve their security posture and meet your company’s expectations.
Embed audits in your overall risk-management programme
Supplier audits should not sit in isolation — they should be part of your overall risk-management strategy. Embedding audit findings into your global risk-management programme improves your ability to anticipate and handle potential threats. Key points:
- Prioritise risks: based on audit results, identify the highest-risk suppliers and build action plans to reduce those risks.
- Implement corrective measures: when gaps are detected, work with suppliers to fix those vulnerabilities as quickly as possible.
- Track risks continuously: include audit information in your risk-management dashboard, to track the evolution of threats and corrective actions.
Tools and technologies to automate supplier cybersecurity audits
Manual supplier audits can be complex and time-consuming, especially with many partners. Technology solutions can automate all or part of the audit process and help you track your ecosystem’s security in real time. Key options:
Automated third-party risk management
Third-party risk-management solutions let you automate supplier evaluations against predefined security criteria. These platforms centralise supplier information and assign risk scores based on compliance with cybersecurity standards and regulations. Key features:
- Automated evaluation: tools continuously analyse supplier security practices using public data, prior audits and supplier-shared information.
- Real-time dashboards: see each supplier’s risk level at a glance and quickly identify those needing attention.
- Automatic alerts: platforms can generate alerts when a supplier’s security score drops or a new vulnerability is detected.
Corrective-action tracking
Once vulnerabilities are identified, you must ensure suppliers take the needed steps to remediate. Corrective-action tracking tools let you monitor implementation and ensure rigorous follow-up:
- Real-time tracking: corrective actions taken by suppliers are tracked live, so you can verify proper implementation.
- Progress reports: tools automatically generate reports on the status of fixes, making internal stakeholder communication easier.
- Post-action assessment: after measures are implemented, you can run a new assessment to verify effectiveness.
Customised report generation
Automated audit solutions also generate customised reports that can be tailored to your specific needs. This simplifies information sharing with leadership, compliance teams and other stakeholders. These reports can include:
- Overall supplier security score: an overview of each supplier’s cyber risk level, based on objective criteria.
- Vulnerability details: a summary of identified security flaws and recommended corrective actions.
- Compliance tracking: the report can indicate whether the supplier meets regulatory requirements such as GDPR, DORA, NIS 2 or ISO standards.
Integration with your SaaS solution
Many companies adopt SaaS solutions to automate and centralise cybersecurity management. If you already use a SaaS platform to steer security and compliance, it must be able to integrate with your supplier-audit tools. Such integration lets you:
- Centralise risk management: all supplier information sits in one tool, simplifying day-to-day management.
- Automate regular audits: the SaaS platform can schedule and automatically run periodic audits.
- Simplify communication: reports and alerts generated by your SaaS platform can be shared with internal stakeholders, providing full transparency on third-party security.
A supplier cybersecurity audit is a must for any organisation aiming to protect its systems and data. By anticipating third-party risks, you strengthen not only your own security posture but also your entire digital ecosystem.
Running regular audits surfaces potential gaps and triggers corrective actions before they become exploitable vulnerabilities. Whether through process assessments, penetration tests or continuous monitoring, each step brings you closer to stronger cybersecurity.
Automating the audit process with fit-for-purpose SaaS solutions boosts efficiency while reducing risk. You can focus on what matters: keeping your infrastructure and customers safe.
For a modern company subject to ever-stricter regulations such as GDPR, DORA and NIS 2, auditing suppliers is no longer optional — it is a strategic necessity. Do not let security gaps at your partners become entry points for cyberattacks.
FAQ
What are the key steps of a supplier cybersecurity audit?
The main steps include risk assessment, security-process analysis, penetration testing and continuous monitoring.
Why is it crucial to audit suppliers regularly?
Regular audits maintain a high security level and ensure suppliers follow best practices for data protection.
Which tools automate supplier cybersecurity audits?
SaaS solutions can automate risk management, corrective-action tracking and custom-report generation.
