Essential ISO 27001 Controls to Strengthen Your Security

Implementing ISO27001 can feel overwhelming at first glance. With its broad range of controls and requirements, many organisations struggle to know where to focus their efforts.

The truth is, not all controls are created equal, and prioritising the right ones can make a significant difference to your security posture.

In this blog, we’ll break down the most critical ISO 27001 controls, why they matter, and how to implement them effectively in your organisation.

What Are ISO 27001 Controls?

ISO 27001 includes a comprehensive set of security controls, listed in Annex A of the standard. These controls cover a wide range of areas, from physical security to access management, and are designed to mitigate risks identified during your risk assessment.

However, ISO 27001 doesn’t require you to implement all the controls in Annex A. Instead, you’re expected to select the controls that are relevant to your organisation, based on the risks you face. This risk-based approach ensures that your resources are focused on the areas that matter most.

The Top ISO 27001 Controls to Prioritise

To simplify your implementation process, here are five of the most impactful ISO 27001 controls to focus on:

1. Access Control

Who has access to your systems and data? Without proper access control, sensitive information can easily fall into the wrong hands.

Key steps to strengthen access control:

• Enforce least privilege: Employees should only have access to the data and systems they need to perform their jobs.
• Use Multi-Factor Authentication (MFA): Add an extra layer of protection for critical systems.
• Review access regularly: Conduct periodic audits to ensure permissions are still valid.
• Revoke access promptly: When employees leave or change roles, ensure their access is removed immediately.

Strong access control minimises the risk of insider threats and unauthorised access.

2. Secure Configuration Management

Default settings are often designed for ease of use, not security. Secure configuration management ensures your systems are hardened against attacks.

Key actions for secure configurations:

• Disable unnecessary features: Remove default accounts, services, and ports that aren’t required.
• Follow hardening guidelines: Use benchmarks like the CIS Controls or NIST standards to configure systems securely.
• Change default passwords: Factory-set passwords are one of the easiest ways for attackers to gain access.
• Automate enforcement: Use tools to monitor and enforce secure configurations across your infrastructure.

By eliminating weak default settings, you significantly reduce your exposure to common vulnerabilities.

3. Cryptography

Sensitive data needs to be protected at all times—whether it’s being stored, transmitted, or processed. Cryptography ensures your data remains confidential and secure.

Best practices for cryptography:

• Encrypt data in transit and at rest: Use strong encryption algorithms like AES-256.
• Implement HTTPS: Secure all web communications with TLS certificates.
• Manage encryption keys carefully: Use hardware security modules (HSMs) or similar solutions to protect your keys.
• Use secure protocols: Avoid outdated protocols like SSL or older versions of TLS.

Cryptography is critical for safeguarding sensitive client data, financial records, and intellectual property.

4. Incident Management

When a security incident occurs, every second counts. An incident management process ensures your organisation can respond quickly and effectively.

Key elements of incident management:

• Create an incident response plan: Define clear roles, responsibilities, and processes.
• Detect incidents early: Use monitoring tools and threat intelligence to identify issues before they escalate.
• Test your response: Run tabletop exercises and live simulations to ensure your plan works under pressure.
• Learn from incidents: Conduct post-incident reviews to improve your processes.

With a strong incident management process, you can minimise the impact of security breaches and recover faster.

5. Supplier Security

Your security is only as strong as your weakest link—and in many cases, that link is a supplier or third-party vendor.

Steps to manage supplier security:

• Conduct due diligence: Assess the security practices of suppliers before onboarding them.
• Include security clauses in contracts: Specify requirements for data handling, incident reporting, and audits.
• Monitor compliance: Regularly review suppliers to ensure they meet your standards.
• Limit access: Only give suppliers access to the systems and data they need.

Supplier security ensures that your third parties don’t introduce unnecessary risks to your organisation.

How to Select the Right Controls

The controls you prioritise should be based on your organisation’s specific risks, as identified during your risk assessment. Ask yourself:

• Which assets are most critical to our business?
• What threats are most likely to affect us?
• Where are we most vulnerable?

Your Statement of Applicability (SoA) will document the controls you’ve chosen to implement and justify why others are excluded. This ensures your approach is focused and aligned with ISO 27001 requirements.

Common Challenges (and How to Overcome Them)

• Challenge: “It’s hard to know where to start.”
• Solution: Begin with your risk assessment. It will guide you to the areas that need the most attention.
• Challenge: “Employees don’t follow policies.”
• Solution: Provide regular training and ensure policies are practical and easy to understand.
• Challenge: “Keeping up with evolving threats is difficult.”
• Solution: Embrace the Plan-Do-Check-Act (PDCA) cycle to review and improve your controls continuously.

The Business Impact of Strong Controls

Implementing the right ISO 27001 controls doesn’t just protect your organisation—it drives real business value:

• Reduced Risks: Proactively addressing vulnerabilities minimises the likelihood of incidents.
• Improved Compliance: Demonstrating strong controls satisfies regulatory and client requirements.
• Enhanced Reputation: Clients and partners trust organisations that prioritise security.

Final Thoughts

The success of your ISO 27001 implementation depends on your ability to prioritise and implement the right controls.

By focusing on areas like access control, secure configurations, and incident management, you can build a robust ISMS that protects your business from today’s threats.

Ready to strengthen your security? Let’s discuss how to implement the right controls for your organisation.

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Check out our guide to ISO27001:2022 ANNEX Controls