ISO 27001:2022 Annex A 8.21: Managing Security of Network Services
Let’s be honest: without a network, your business probably grinds to a halt. Whether it is sending emails, accessing the cloud, or just letting your team talk to one another, network services are the invisible backbone of modern operations. But here is the catch—just because you pay an Internet Service Provider (ISP) or a cloud host, it doesn’t mean your security is automatically sorted. ISO 27001:2022 Annex A 8.21 exists to close that gap. It ensures that the network services you use—whether in-house or outsourced—are secure, monitored, and actually delivering what they promised.
Table of contents
What is Annex A 8.21?
In the simplest terms, Annex A 8.21 requires an organization to ensure that security mechanisms, service levels, and management requirements for all network services are identified, implemented, and monitored. Think of it as the “quality control” for your connections. It forces you to stop assuming your network providers are doing a good job and start verifying it. This applies to a wide range of services, including: Standard Internet Service Providers (ISPs). Cloud connectivity (IaaS/PaaS). Managed Firewalls and VPNs. Wide Area Networks (WANs) and SD-WANs. You can view the full list of controls and how they fit together on ISO27001.com.
Why This Control Matters
If you ignore this control, you are essentially outsourcing your risk without any oversight. If your ISP has a breach, or your cloud provider drops their encryption standards without telling you, your data is exposed. Annex A 8.21 acts as a preventive control to stop these issues before they become full-blown incidents.
Key Components of Implementation
To get this right, you need to move beyond just looking at “uptime” and start looking at security. Here is how you can break it down.
1. Service Level Agreements (SLAs)
The heart of this control is the agreement you have with your provider. A standard contract might promise 99.9% uptime, but does it promise to encrypt your data? Does it specify how quickly they will patch a vulnerability? You need to ensure your SLAs cover: Security Features: Explicitly state what security the provider handles (e.g., firewall management, DDoS protection). Service Levels: Define clear metrics for performance and response times during a security incident. Right to Audit: Can you check their work? Or at least see their third-party audit reports (like a SOC 2 report)?
2. Identify Your Security Requirements
You cannot hold a vendor accountable if you don’t know what you need. Before signing a contract, you must define the security requirements for that specific service. For example, if you are setting up a secure VPN for remote workers, your requirements might include “Multi-Factor Authentication (MFA)” and “End-to-end Encryption.” If you are just buying basic office Wi-Fi, the requirements might be lower. Documenting these requirements proves you are making informed decisions.
3. Monitoring and Review
You signed the contract—great. Now, are they actually doing the work? Annex A 8.21 requires ongoing monitoring. This doesn’t always mean you need a team of engineers watching traffic 24/7 (though that helps). It can be as simple as: Regularly reviewing reports provided by the service provider. Checking logs to ensure agreed-upon security controls (like firewalls) are active. Holding quarterly or annual review meetings with major providers to discuss performance and security incidents.
Practical Implementation Steps
If you are wondering where to start, follow this simple roadmap: Step 1: Create a Network Services Inventory. List every network service you pay for or use. You would be surprised how many businesses lose track of old VPNs or secondary internet lines. Step 2: Risk Assess the Providers. Not all networks are equal. Your main data center link is higher risk than the guest Wi-Fi in the lobby. Treat them accordingly. Step 3: Update Your Contracts. Next time a renewal comes up, check the clauses. Are security responsibilities clearly defined? If not, negotiate them in. Step 4: Define “Allowed” Services. Make it clear to your employees which network services are authorized. Shadow IT (using unauthorized services) is a major way this control gets bypassed.
Common Challenges
The biggest headache here is usually leverage. If you are a small business dealing with a giant telecom provider, you probably can’t rewrite their standard contract. In these cases, your “monitoring” shifts to due diligence. You must review their public security certifications (like their own ISO 27001 certificate) to satisfy your risk assessment. Another challenge is the technical skill gap. If you don’t have internal network engineers, you may need to rely on third-party experts to help you define what “good” looks like in an SLA.
Conclusion
ISO 27001:2022 Annex A 8.21 isn’t just about technical settings on a router; it’s about vendor management and accountability. By clearly defining what you need and checking that you are getting it, you ensure that your business’s digital lifeline remains secure, reliable, and compliant.
