Security Island: what is it and how to prevent it?

Written by Ivar van Duuren

April 20, 2023

security island

You’ve probably heard of the term security island. But what exactly is it? And is it a desirable or undesirable situation? In this article, we address these questions so you can better understand what a security island is and how to deal with it.

What is a security island?

A security island is the term to describe an isolated sub-area of a computer system with limited or no access to other parts of the network. The security island comes with its own security components that manage data, access control, compliance, and so on, without centralized oversight. A security island can include both physical and virtual networks, such as cloud-based systems.

The goal is to make it more difficult to manage the security of the entire system as a whole. This also means that if one part of the network is hacked, access to other parts is blocked. This makes it more difficult for attackers to penetrate the entire network at once.

The concept of a security island is similar to that of a segregation model in which different areas remain separate. In computer systems, networks are often physically separated by firewalls and other boundary devices.

How does an unwanted security island arise?

A security island can arise for a variety of reasons. But when something like this occurs unplanned, it often stems from poor configuration within an organization’s network infrastructure.
For example, if certain systems are not properly configured or monitored, they become a vulnerable target for attackers. These then use this target to gain access to other systems on the same network. 

In addition, organizations may not realize that certain devices such as printers or switches are connected directly to their networks. This makes them vulnerable access points for malicious actors looking for backdoors into computer systems.

Finally, organizations may forget about legacy systems that have been abandoned but are still present on their networks. These then provide possible routes into their core infrastructure.

Why is a security island not desirable?

A security island is generally undesirable because it creates a hole in an organization’s overall security. This makes it easier for attackers to exploit these weaknesses. Therefore, the risk of such a hack being detected or stopped quickly is low.

Moreover, these holes can lead to the misappropriation or appropriation of sensitive data and information. Because hackers use these unsecured points to gain access to sensitive information stored in the system itself. Or they use an unsecured access point as a springboard to larger corporate networks containing confidential customer data or critical business information. The consequences of the misappropriation of such information, for most organizations, are disastrous.

Also read: Tips for creating information security policies

7 Tips to prevent a security island

Prevention is always better than cure when it comes to security islands. But how do you make sure the network stays secure?

1. Perform regular vulnerability checks

Organizations should perform regular checks to identify vulnerabilities in their network infrastructure. They should also ensure that all necessary patches and updates have been applied. This will make it less easy for malicious actors to exploit known vulnerabilities.

2. Use firewalls

Firewalls act as gatekeepers between different parts of your organizational network and you need to configure them properly. This means setting up appropriate rule sets based on your specific needs.

For example, consider setting up whitelists that allow only certain types of traffic through and block everything else. That way, potential fishing emails or other threats won’t even have a chance to penetrate the system.

3. Get your organization ISO 27001 certified

The ISO 27001 standard provides a strong foundation for a comprehensive information and cyber security strategy for any organization, regardless of size or sector. The standard outlines a best practice ISMS framework to mitigate risk and protect business-critical data through identification, analysis and actionable controls.

An accredited ISO 27001 certification demonstrates that your organization has the processes and controls in place to protect sensitive information in an increasingly complex digital world.

4. Monitor network traffic

Monitoring traffic going both ways across the corporate network (inbound and outbound) helps identify suspicious activity. Consider, for example, attempts to access unauthorized resources or suspicious file transfers occurring through insecure channels. If something unusual happens, it is important to investigate it immediately before further damage occurs.

5. Implement a segmentation policy

Also consider implementing a segmentation policy where different parts of the network are separated from each other. Even if one part of the network is compromised, malicious actors cannot take down the entire network at once.

This type of setup requires a good understanding of where each device is located within the network structure. Only then can you set up the right firewall ruleset.

6. Use Intrusion Detection Systems

Intrusion Detection Systems (IDS) monitor traffic patterns 24/7 across the network environment. They aim to detect suspicious activity that indicates malicious intent. Examples include login attempts, network scans, etc.

If something abnormal happens, an IDS sends an alert so the IT team can respond quickly before serious damage occurs.

7. Educate employees about cybersecurity risks

Since many cybersecurity vulnerabilities do involve human actions, awareness of the dangers is very important. Consider an employee who shares important data with malicious parties via a phishing email without being aware of it.

It is therefore important to train employees on cybersecurity risks. Such as what social engineering attacks are, how phishing scams work et cetera. An effective cyber awareness training program ensures that everyone is vigilant when using the Internet.

Also read: Tips for security (risk) awareness in information security


A security island created in your network structure is an undesirable situation because it makes the network more vulnerable to attacks. By carefully following the above steps, you can better protect your organization from potential attacks on the network.

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