Introduction: Beyond the Jargon
For high-growth AI companies, navigating the world of information security compliance can feel like a distraction from the core mission of innovation. Frameworks like ISO 27001, with their structured clauses and controls, can seem abstract and disconnected from the fast-paced reality of developing and deploying algorithms. However, these standards are not just bureaucratic hurdles; they are essential frameworks for building the trust, resilience, and operational discipline necessary to protect your most valuable assets and secure your place in the market.
At the heart of a resilient security program is the ability to respond effectively when things go wrong. This is the core purpose of ISO 27001 Annex A 5.25 Assessment and decision on information security events/ In simple terms, this control requires you to have a systematic process for looking at any security-related “event” that occurs and deciding if it is serious enough to be escalated and treated as a security “incident.”
The goal of this guide is to translate the formal requirements of Control 5.25 into a practical, actionable framework specifically for businesses operating with complex AI workflows. We will demystify the control’s purpose and provide clear steps to implement it in a way that strengthens, rather than stifles, your operations. To begin, we must first address the critical first step: understanding the fundamental difference between an everyday security event and a genuine security incident within the unique context of your AI environment.
Table of contents
- Introduction: Beyond the Jargon
- The Core Challenge: What’s an ‘Event’ vs. an ‘Incident’ in Your AI Environment?
- A Deep Dive into AI-Specific Risks
- Your Action Plan: Implementing Control 5.25
- The Solution: Achieving Compliance with the High Table ISO 27001 Toolkit
- Conclusion: From Compliance Hurdle to Business Resilience
The Core Challenge: What’s an ‘Event’ vs. an ‘Incident’ in Your AI Environment?
The strategic importance of correctly distinguishing between an information security event and an incident cannot be overstated. This can lead to two equally damaging outcomes: wasting precious resources by treating every anomaly as a five-alarm fire, or, more dangerously, underestimating a genuine threat and finding yourself unprepared when a real attack occurs. The key is to develop a clear, consistent, and documented approach to this critical decision-making process.
ISO 27001 defines an event as any observable occurrence in a system or network. This could be anything from a failed login attempt to a firewall alert. An incident, on the other hand, is an event that compromises or threatens your information assets – specifically their Confidentiality, Integrity, or Availability (the “CIA Triad”).
For an AI company, these definitions take on a unique meaning. The following table translates general incident categories into the specific, high-stakes scenarios your business faces.
| General Incident Type | What This Means for Your AI Company |
|---|---|
| Unauthorised access to information systems | Unauthorised access to your model training environments, cloud-based GPU clusters, or MLOps pipelines. |
| Unauthorised disclosure of information | A leak of sensitive or proprietary training datasets, which could include personally identifiable information (PII) or your core intellectual property. |
| System outage | A disruption of your critical inference APIs, preventing customers from using your service, or a failure in the algorithmic processes that drive your product. |
| Unauthorised modification of information | A sophisticated model poisoning or data poisoning attack that deliberately alters your algorithm’s behaviour, leading to biased, incorrect, or harmful outputs. |
Understanding these potential incidents is the first step; the next is to perform a deeper analysis of the unique assets you need to protect.
A Deep Dive into AI-Specific Risks
For an AI company, the “information assets” at risk extend far beyond traditional databases and customer lists. Your core intellectual property – and therefore your competitive advantage – is embedded in your models, proprietary algorithms, and specialised data pipelines. Applying Control 5.25 effectively means extending your security monitoring and assessment to these unique assets.
Protecting Your Training Data and Models
Your training datasets are among your most valuable assets. A data leak isn’t just a privacy breach; it can be an act of corporate espionage that erodes your R&D investment and market position. Under Control 5.25, an event like unusual data access patterns from a new IP address must be formally assessed. The key question to answer is: could this event escalate into a catastrophic incident, such as the exfiltration of the dataset that powers your flagship model? A structured assessment process ensures such events are never dismissed without proper evaluation.
Ensuring Algorithmic Integrity
The integrity of your models is a direct reflection of your brand’s credibility. An event such as a sudden degradation in model performance or a series of unexpected outputs requires a formal assessment. While it might be a benign data anomaly, it could also be the first sign of a security incident, such as a data poisoning attack. This isn’t just a technical failure; it’s a direct threat to your brand reputation and customer trust. What is the financial and reputational cost if your predictive model starts giving dangerously flawed outputs?
Securing the AI Supply Chain
Modern AI development rarely happens in a vacuum. Your AI supply chain includes third-party datasets, pre-trained models, and cloud platforms. An event here could be a security alert from a key supplier. Your assessment process must evaluate these external events and determine if they constitute a potential incident impacting your own posture. This requires close alignment with Control 5.22 (Monitoring, Review and Change Management of Supplier Services) and Control 5.23 (Information Security For The Use of Cloud Services), as these are foundational components of most AI technology stacks.
Having identified these specific risks, we can now turn to the practical steps required to build a robust process for managing them.
Your Action Plan: Implementing Control 5.25
Implementing Control 5.25 does not need to be a complex or bureaucratic exercise that hinders innovation. Instead, think of it as creating a simple, repeatable playbook that provides the structure for secure growth. The following five steps provide a clear path to establishing an effective assessment and decision-making process.
Establish Your Assessment Framework
You must create clear, documented criteria for categorising events. This removes guesswork and ensures consistency. A proven method is to assess events based on their potential business impact and the urgency required for a response. This can be expressed with a simple formula: Impact x Urgency = Priority. Document this in a straightforward matrix that your team can reference quickly.
| Priority Level (Severity) | Potential Business Impact | Example | Response Time |
|---|---|---|---|
| Low | No service disruption; single non-critical asset affected. | A single blocked phishing email reported by an employee. | 24 Hours |
| Medium | Limited service impact; potential for non-sensitive data exposure. | Malware detected and quarantined on one employee’s laptop. | 4 Hours |
| High | Critical service degradation; potential for sensitive data exposure or impact on model integrity. | Ransomware detected on a development server containing training data. | 1 Hour |
| Critical | Major service outage or data breach; existential threat to operations or reputation. | A confirmed leak of a proprietary model or customer database. | Immediate |
Assign Clear Roles and Responsibilities
Designate a specific point of contact or a small, dedicated team responsible for assessing security events. This does not need to be a full-time role in a smaller organisation, but accountability must be clear. This person or team is responsible for using the assessment framework to formally decide if an event should be escalated and declared an incident, thereby triggering your broader incident response plan.
Document Everything Methodically
During an ISO 27001 audit, if it isn’t written down, it didn’t happen. For every significant event that is assessed, you must record the results. This log should include the date, nature of the event, assessment of impact and urgency, the final decision, and the rationale. This record serves as a defensible audit trail demonstrating due diligence. Furthermore, this documentation is crucial evidence not just for 5.25, but also for Control 5.28 (Collection of Evidence) if an incident leads to legal action, and for Control 5.27 (Learning from Information Security Incidents).
Train Your People
Technology and processes alone are not enough. All employees should be aware of how to report a potential security event. The individuals assigned to the assessment role must be trained on the framework and criteria to ensure they can make consistent, effective, and defensible decisions. Remember, while automated tools can flag events, the final, nuanced decision to classify an event as an incident often relies on trained human judgment.
Institute a Review and Learn Process
After an event is assessed (and if necessary, handled as an incident), the process is not over. The assessment itself, the decision, and the outcome should be reviewed. This learning loop is fundamental to the principle of continual improvement (ISO 27001 Clause 10.2). Use these reviews to refine your assessment criteria, improve response times, and identify recurring issues that may point to deeper vulnerabilities.
Following this action plan will put you on a clear path to compliance. To accelerate implementation, you can leverage a purpose-built solution.
The Solution: Achieving Compliance with the High Table ISO 27001 Toolkit
The most logical and practical way to implement the action plan described above is by using the High Table ISO 27001 Toolkit. This toolkit is designed to provide the foundational documents and structure needed to build a compliant information security management system without starting from scratch.
The toolkit directly solves the core challenges of implementing Control 5.25 by providing the necessary governance structure and documentation. It includes essential, auditor-ready templates, such as a pre-written Incident Management Procedure. This single document provides the framework for your assessment criteria, roles, and responsibilities – and while a formal procedure isn’t mandatory, it is the most effective and expected way to provide the clear, consistent evidence that an auditor will require to verify compliance.
For an innovative AI business, a toolkit offers a crucial advantage over more rigid online platforms or SaaS solutions. The templates provide a strong, compliant foundation but offer the flexibility you need to tailor your incident response processes to your unique AI workflows and technology stack. You are not locked into a predefined structure that doesn’t account for risks like model poisoning or data pipeline security.
The High Table ISO 27001 Toolkit provides the auditor-ready documentation you need, giving you the control to build a robust and flexible incident assessment process that protects your unique AI assets.
You can find the High Table ISO 27001 Toolkit here: https://hightable.io/product/iso-27001-templates-toolkit/
This toolkit provides the essential components, allowing you to focus on adapting them to your business rather than creating them from nothing.
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Conclusion: From Compliance Hurdle to Business Resilience
This guide has broken down ISO 27001 Annex A 5.25 into a clear, manageable process tailored for AI companies. We have moved from defining events versus incidents in an AI context to identifying specific risks and outlining a five-step action plan for implementation.
Ultimately, effectively implementing this control is not just about passing an audit. It is about safeguarding the very engine of an AI business – its intellectual property and decision-making systems. By creating a structured process to assess and learn from threats, you are proactively protecting your critical assets, mitigating operational risk, and enhancing stakeholder trust. This is how a perceived administrative burden is transformed into a core pillar of business strategy.
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.
