Understanding Your Obligations Under Annex A 5.21
For a modern AI business, the pace of innovation is relentless. To stay competitive, you rely on a complex ecosystem of third-party products and services – from cloud computing platforms to specialized data providers. While this strategy accelerates development, it also introduces significant, often hidden, security risks within your supply chain. Managing these dependencies is no longer just an IT issue; it is a strategic imperative for protecting your intellectual property and maintaining operational resilience.
The international standard for information security, ISO 27001, directly addresses this challenge through ISO 27001 Annex A 5.21 Managing information security in the ICT supply chain. The core requirement of this control is for your organization to define and implement processes and procedures “to manage the information security risks associated with the ICT products and services supply chain.”
The purpose of this control is fundamentally preventative. It is designed to help you “maintain an agreed level of information security in supplier relationships,” ensuring that vulnerabilities from your partners do not become your own security incidents. For a business built on data and algorithms, understanding and implementing this control is a critical step in securing the very foundation of your innovation.
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Why Your AI Supply Chain Presents Unique Security Challenges
An AI company’s supply chain is often far more complex and dynamic than that of a traditional technology firm. It involves a wide and evolving range of specialized suppliers for data, pre-trained models, annotation services, and high-performance computing infrastructure. This section analyzes the specific vulnerabilities that arise from these unique and critical relationships.
The scope of an Information and Communication Technology (ICT) supply chain is broad, encompassing all external parties that provide ICT-related products or services. This includes hardware and software vendors, cloud service providers, managed service providers (MSPs), and outsourced development teams. For an AI company, these supplier categories map directly to core operational functions, each with distinct risks that demand sophisticated management.
- Data Sourcing and Annotation: Partners providing datasets or data labelling services are a fundamental part of your ICT supply chain. This creates a significant risk of data breaches due to poor supplier controls. This risk is amplified in AI because annotation partners often handle raw, un-sanitized, and potentially sensitive data that may not yet be subject to your company’s full production data protection policies, making their security posture a direct extension of yours.
- Model Development and Training: This layer includes cloud providers offering specialized GPU resources, vendors of pre-trained foundational models, and developers of essential software libraries. A key risk here is the introduction of malicious code or backdoors in software or firmware. Beyond generic malware, AI companies face the specific threat of model poisoning or tampered pre-trained models that can subtly corrupt your results or steal proprietary data.
- Deployment and Operations: Once a model is deployed, it relies on hosting services and managed service providers who run and monitor your inference endpoints. These relationships introduce the risk of service interruptions from supplier failure and a lack of visibility into your supplier’s own supply chain (fourth parties). For example, your cloud provider (third party) may rely on a specific hardware vendor (fourth party) for its GPUs. A vulnerability in that hardware’s firmware could directly compromise your model inference.
These heightened dependencies mean that a security failure anywhere in your AI supply chain can have immediate and severe consequences for your business, making a structured mitigation strategy non-negotiable.
Your Action Plan for Securing the AI Supply Chain
Compliance with Annex A 5.21 is not a bureaucratic exercise; it is the operational blueprint for de-risking your innovation. This action plan moves from theory to execution, providing a roadmap to build a resilient and defensible AI supply chain.
Establish Your Governance Framework
Your first step is to establish a single, non-negotiable set of information security standards. This involves creating a central, authoritative source that defines your expectations for every supplier.
- You must draft a comprehensive set of information security standards tailored to your organisation’s specific needs, articulating your requirements for everything from access control to incident reporting.
- These standards must be formally documented in a Supplier Security Policy or a Procedure for Managing Supplier Security Risks. This document becomes the foundation for all your supplier security activities and a key piece of evidence for an ISO 27001 audit.
Scrutinise Your AI Partners and Tools
With your governance framework established, you must apply it with rigorous, evidence-based due diligence. Every third-party tool, dataset, or platform must be scrutinized before it touches your production environment. Assume nothing; verify everything.
- Demand Transparency: You need a clear understanding of what you are integrating. Request detailed information from suppliers about their software components and security functions. For an AI company, this means mandating a Software Bill of Materials (SBOM) for any third-party model or library, understanding the data handling policies of an annotation service, and knowing the specific security configuration required for a third-party model API.
- Identify Critical Components: Identify and document the components and services essential for your core functionality, such as a specific data annotation service or a specialized cloud computing provider. You must obtain assurance from your supplier that these components can be traced throughout their entire lifecycle, from origin to delivery.
- Get Assurance: Do not rely on promises alone. Obtain formal assurance that your suppliers’ ICT products and services meet required security levels. The most effective way to do this is by validating their existing security certifications, such as ISO 27001 or SOC 2, which provide third-party verification of their security posture.
- Verify Secure Implementation: Don’t just accept a product; verify its secure configuration. Require suppliers to provide detailed security hardening guides for their APIs, models, or platforms, and validate that your engineering teams are implementing them correctly.
Enforce Security Through Agreements and Monitoring
Your security standards must be enforceable and consistently applied. This requires embedding them into your legal agreements and establishing a process for ongoing oversight.
- Include specific, detailed security clauses in all supplier contracts and service level agreements. This makes your security requirements legally binding.
- Require your suppliers to propagate the organisation’s security standards to their subcontractors. This is critical for managing fourth-party risk and ensuring security is maintained throughout the entire chain.
- Security is not a “set it and forget it” activity. You must implement processes to monitor and validate supplier compliance with your requirements on an ongoing basis. This can be achieved through periodic reviews, performance metrics, and formal audits.
Formalizing these processes in audit-ready documentation is not only a compliance requirement but the foundation of a scalable supplier management program.
The High Table Toolkit: Your Path to Compliance
Implementing the action plan required by Annex A 5.21 involves creating structured, comprehensive documentation that can be challenging and time-consuming to develop from scratch. The High Table toolkit provides a practical and efficient solution to this challenge, enabling you to build a robust governance framework quickly.
As recommended by ISO 27001 best practices, the necessary documentation includes a formal Supplier Security Policy and a comprehensive ISO 27001 Supplier Register.
The High Table ISO 27001 Toolkit, available at https://hightable.io/product/iso-27001-templates-toolkit/, provides the exact templates and policies you need to meet these requirements.
This toolkit directly addresses the compliance challenges faced by a growing AI company, offering tangible benefits that accelerate your path to certification and beyond.
- Establish Authoritative Standards: The Supplier Policy Template provides auditor-approved language to codify your security expectations, eliminating guesswork and creating a single source of truth for all supplier engagements.
- Organise Your Partners Systematically: The included Supplier Register Template provides a structured way to effectively document, track, and manage all your ICT suppliers. This central record is essential for managing everything from your primary cloud provider to specialized data annotation services.
- Simplify Audits: An ISO 27001 auditor will look for evidence of a formal process for managing supply chain risks. Using these structured templates provides clear, audit-ready documentation that demonstrates your commitment to the standard and simplifies the audit process.
Ultimately, the High Table toolkit is more than a set of documents; it is a strategic asset that provides the essential governance structure to secure your AI supply chain, protect your intellectual property, and build lasting trust with your customers.
Conclusion: Securing Your Innovation from the Ground Up
The complex, interconnected nature of the modern AI supply chain makes it a primary source of information security risk. Dependencies on third-party data, models, and infrastructure create vulnerabilities that can undermine your innovation and expose your business to significant threats. However, ISO 27001 Annex A 5.21 provides a clear and effective framework for managing these challenges head-on.
By implementing a systematic approach to supplier security – from establishing a robust governance policy to enforcing standards through contracts and ongoing monitoring – you can protect your core assets and build a more resilient organization. Robust supply chain security is not just a competitive advantage; it is a non-negotiable prerequisite for earning the trust of enterprise customers and unlocking the higher-value contracts that drive sustainable growth and protect the innovation at the heart of your business.
About the author
Stuart Barker is a veteran practitioner with over 30 years of experience in systems security and risk management.
Holding an MSc in Software and Systems Security, Stuart combines academic rigor with extensive operational experience. His background includes over a decade leading Data Governance for General Electric (GE) across Europe, as well as founding and exiting a successful cyber security consultancy.
As a qualified ISO 27001 Lead Auditor and Lead Implementer, Stuart possesses distinct insight into the specific evidence standards required by certification bodies. He has successfully guided hundreds of organizations – from high-growth technology startups to enterprise financial institutions – through the audit lifecycle.
His toolkits represents the distillation of that field experience into a standardised framework. They move beyond theoretical compliance, providing a pragmatic, auditor-verified methodology designed to satisfy ISO/IEC 27001:2022 while minimising operational friction.
