What Is Network Segmentation and Why Does It Matter?

Explore the concept of network segmentation, its benefits and its importance in protecting modern networks.

imageToday's increasingly interconnected world has prompted network security to become a high priority for organizations of all sizes. One essential component of network security is network segmentation. In recent years, there has been a great deal of interest in network segmentation due to its effectiveness at mitigating potential risks and minimizing the severity of security incidents. Ultimately, there is no substitute for network segmentation when protecting your data.

We’ll explore the concept of network segmentation, its benefits and its importance in protecting modern networks. We'll provide valuable insights into the world of network segmentation, how it can be used effectively to better secure your network and how it is key to navigating the digital frontier more securely.

What Is Network Segmentation?

Network segmentation is when different parts of a computer network, or network zones, are separated by devices like firewalls, switches and routers. Network segmentation is a discipline and a framework that can be applied in the data center and on-premises at an organization's facilities.

Why Is Network Segmentation Important?

Today, the workload on internet firewalls has reached an all-time high. They handle everything from real-time learning behavioral analytics to accepting necessary cookies for user experience. While firewalls are strict and adhere to a set of established rules, they alone cannot fully protect your digital assets. Additionally, firewalls can become obsolete within a generation.

Your systems deserve to be protected, and there needs to be an additional layer of security beyond the front lines of the internet firewall. Remember, firewalls aren't just for the perimeter of your network. They should also be strategically deployed within your network to add an extra layer of inspection and control between critical network segments.

What happens when a threat actor penetrates the internet firewall through a phishing attempt? Systems and services need to be isolated from each other in order to prevent a minor breach from becoming a significant security incident that leads to a larger compromise of organizational digital assets and data.

It’s one thing to have your video cameras compromised, but it’s another to have your customer data stolen. Both scenarios are common in many businesses, but they do not pose the same level of risk and liability to the business assets.

If the business in the above example practices proper network segmentation and their video cameras are compromised (which isn’t uncommon), the threat actor will encounter another obstacle while trying to infiltrate the network. Essentially, it’s like turning a corner in a hedge maze only to find a dead end. The threat actor will have to work their way backward and attempt to find other access points to the systems and data they are attempting to exploit. At this point, many cybercriminals will get discouraged and start looking for an easier target.

Whether you are running a virtual local area network (VLAN) on-premises at your organization's facilities or running a software defined networking (SDN) architecture in your hybrid cloud or server virtualization platform, network segmentation protects your assets more effectively.

Types of Network Segmentation

A common question that is asked is, “How do you know what network zones your organization needs?” Think about the different types of users and data you have and who needs access to what.

Here are some examples of the types of network zones you may want to establish:

  • Users: Users work in different departments and often have different data access needs. You should segment those departments based on those access needs. The idea here is that you are adding a different layer of protection for each department on your network.
  • DMZ subnet: This includes the subnetworks that expose externally facing systems – where the handshakes take place on your network. For example, it may include public-facing websites or other resources accessible via the internet. You want to separate things that the public can access from your local area network (LAN), as well as internal data that needs to be protected.
  • Wi-Fi networks: Guest Wi-Fi should be separate from the corporate Wi-Fi, and both should be segmented from your corporate networks. This may seem like a no brainer, but a lot of smaller businesses never bother to set it up. Even residential routers include this feature – you can easily set up a guest Wi-Fi in your home!
  • IT workstations: Give IT their own network segments for testing, development and management functions. These segments should have very specific controls to manage risks.
  • Servers by application: Create separate segments for application-specific servers. You should be able to isolate servers with confidential or financial data applications on them. This can limit the crawl of malware.
  • VoIP/Communications: Placing communications systems on their own network zone boosts performance and enhances quality. But in terms of network security, they have also become a common attack plane as communications move away from traditional platforms.
  • Traditional physical security: Cameras, ID card scanners, etc., should be in their own network zone. This is not to be taken lightly, as the risk of a physical breach can be more harmful than a digital one. There are numerous real-world examples of this, including an incident in 2017 when the closed-circuit camera network in Washington, D.C. was hacked, leaving police cameras unable to function for three days.
  • Industrial control systems: Industrial control systems are a common point of attack and should be segmented from each other as well as the corporate data network. In addition to segmentation, remote access by vendors who support those platforms should use VPNs and implement multi-factor authentication.
  • Customer databases: Due to compliance requirements, customer databases need to be secured more intently than, for instance, your print server. PCI-DSS, HIPAA, HiTRUST, FINRA, GDPR and other pieces of data legislation will determine the level of segmentation and cybersecurity that would be best practice in terms of implementation.

It's a good idea to configure your routers, switches and firewalls to send logging and event data to your Security Information and Event Management (SIEM) systems to monitor all segmented network zones, as well as the systems that reside on them. Make sure to review your logs or work with an IT partner that will double your vigilance and function as an extra set of eyes.

Moving to the cloud is a legitimate strategy for network segmentation. However, it does not automatically mean it’s easier or more secure for network segmentation. Remember, the cloud is someone else's network, so you need to ensure that you are both protected.

Learn more on
why your cloud solutions deserve zero-trust networking.

Who Needs Network Segmentation?

Everyone running internal systems to meet business needs, whether physical or virtualized, should be concerned with network security. The more complex the architecture, the more important the need for segmentation. The only users who won’t need network segmentation are businesses that are 100% remote and rely entirely on software as a service (SaaS).

If you’re running a flat network to simplify the number of switches, you’re going to be an ideal target for a threat actor. While a flat network may save you time and money in the initial setup, it could leave you vulnerable in the future. This type of easy, lateral movement across the entire network allows adversaries to navigate wherever they want with little to no resistance.

Each customer will require a different level of segmentation. And again, there is no substitute for network segmentation. Implementing micro-segmentation does take some time, but the benefits far outweigh the effort.

Benefits of Network Segmentation

While safety and security are critical benefits in their own right, the following also serve as significant advantages when it comes to network segmentation:

  • Damage control and limitation in case of an incident via the smaller attack surface.
  • Improved access control for both external and internal network security.
  • Reduction of the attack plane and scope of compliance requirements related to auditing.
  • Improved performance due to less congestion in network traffic.
  • Enhanced analytics around network monitoring, network access and network devices.
  • Protection of endpoint devices, which is especially important as Internet of Things (IoT) devices become more common.

Segmenting your network enhances your overall security policy. By limiting users' access privileges to only those who need them, you are safeguarding the network against widespread cyberattacks and improving network performance by reducing user density.

Learn More About Network Segmentation

Network segmentation is covered as part of the CompTIA Security+ exam objectives. CompTIA Security+ equips you with the foundational security skills necessary to safeguard networks, detect threats and secure data – helping you open the door to a cybersecurity career and become a trusted defender of digital environments.

Ready to get started? Learn the skills you need with CompTIA CertMaster Learn + Labs. Sign up for a free 30-day trial today!

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