Divide And Conquer - the benefits of Network Segmentation.

On a recent visit to a business that had "explosive" growth over the last 5 years; I was reminded of how implemented technical solutions need to be continually re-visited and re-appraised.

Giles told me that, as the business grew and their network infrastructure grew increasingly large and complex, it felt like as if "things were grinding to a halt".

Where would we even start?

Within an hour, I knew where we had to start from. The incumbent provider ( a family friend ) had continued using a flat network structure despite the number of network connected assets exploding from 15-20 in 2017 to just over 600 in October 2023.

Divide and Conquer! was going to be my war cry on this latest campaign.

In a nutshell, Network Segmentation is where Larger Networks are broken down into Multiple Smaller Networks for various benefits:

Security Enhancement:

1. Containment of Threats: In a sprawling network, the potential for security breaches looms large. A breach in one area can quickly escalate, jeopardizing the entire infrastructure. Network segregation acts as a virtual fortress, dividing the network into isolated segments or zones. This containment strategy limits the impact of security incidents, preventing malicious actors from moving laterally through the network. By confining breaches to specific segments, organizations can mitigate the risk and reduce the potential damage to critical systems.
2. Compartmentalization for Defense: The principle of least privilege is a cornerstone of cybersecurity, advocating for the restriction of access rights for users, applications, and systems to the bare minimum necessary for their function. Network segregation aligns seamlessly with this principle by compartmentalizing the network into distinct zones based on functionality, sensitivity, or user roles. Critical systems handling sensitive data can be isolated, implementing stringent access controls and additional layers of security. This granularity ensures that even if one segment is compromised, the attacker's ability to move laterally and escalate privileges is significantly curtailed.
3. Isolation of High-Value Assets: In larger networks, identifying and safeguarding high-value assets is imperative. These assets, which often include sensitive databases, intellectual property, or critical infrastructure, are prime targets for cyber adversaries. Network segregation allows organizations to isolate these high-value assets, creating dedicated segments with heightened security measures. This approach ensures that the crown jewels of an organization are shielded behind multiple layers of defense, making it significantly more challenging for attackers to compromise them.
4. Customized Security Measures: Not all segments of a network are created equal. Different areas may have distinct security requirements based on the nature of the data or applications they handle. Network segregation empowers organizations to implement customized security measures tailored to the specific needs of each segment. Critical segments may employ robust encryption protocols, multifactor authentication, and intrusion detection/prevention systems, while less critical areas may have more relaxed security controls. This adaptability allows organizations to strike a balance between security and operational efficiency.

Performance Optimization:

1. Traffic Management and Prioritization: The sheer volume of data traffic in larger networks can lead to congestion and latency issues, affecting overall performance. Network segregation facilitates effective traffic management by dividing the network into segments based on the type of traffic or application. For instance, separating voice and video communication traffic from data traffic ensures a smoother performance for real-time applications. By allocating dedicated segments with higher bandwidth and lower latency to critical business applications, organizations optimize the network's performance, enhancing the overall user experience.
2. Quality of Service (QoS) Implementation: Diverse applications within a network may have varying bandwidth requirements. Network segregation enables the implementation of Quality of Service (QoS) policies, allowing organizations to prioritize certain types of traffic over others. This becomes particularly important in environments where bandwidth-intensive applications coexist. By assigning different levels of priority to different segments, organizations can ensure optimal performance, even during peak usage periods. QoS policies, coupled with network segregation, contribute to the efficient utilization of network resources.
3. Isolation of Resource-Intensive Applications: Some applications within a network may be resource-intensive, requiring significant bandwidth and processing power. Network segregation allows organizations to isolate these applications, preventing them from monopolizing resources and negatively impacting the performance of other critical systems. This targeted isolation ensures that resource-intensive applications operate at peak efficiency without compromising the overall network performance.

Regulatory Compliance:

1. Data Protection and Privacy: The regulatory landscape governing data protection and privacy is evolving rapidly. Legislations such as the General Data Protection Regulation (GDPR), Payment Card Industry Data Security Standard (PCI DSS), and Health Insurance Portability and Accountability Act (HIPAA) impose strict requirements on organizations to safeguard sensitive information. Network segregation plays a pivotal role in achieving and maintaining regulatory compliance by isolating segments that handle regulated data. This isolation allows organizations to implement specific controls and safeguards tailored to the requirements of each regulation.
2. Auditability and Accountability: In the aftermath of a security incident or during compliance audits, the ability to trace and monitor activities within specific segments becomes paramount. Network segregation provides a clear delineation of responsibilities and access privileges, facilitating auditability and accountability. The audit trail within each segment aids in the forensic analysis of security incidents, helping organizations understand the scope and impact of a breach. This transparency is crucial for regulatory compliance and demonstrates a commitment to maintaining the highest standards of security.
3. Compliance with Industry Standards: Various industries have specific security standards and best practices that organizations must adhere to. Network segregation aligns with these industry standards, providing a framework for implementing security controls and measures that meet or exceed the requirements. Whether in finance, healthcare, or critical infrastructure, organizations can leverage network segregation to tailor their security posture to the specific demands of their industry, ensuring compliance and resilience against sector-specific threats.

How to Segment Your Network:

There are three main ways of segmenting your network - although, in general, it is more common to see a solution implemented as a blend of all three.

1. vLAN [ Virtual LAN ] Segmentation

Most network segmentation is achieved using VLANs to create smaller groups of subnetworks or subnets that are connected and share the same physical network in the same location. Only users within the same VLAN can communicate with each other.

In order for users on different VLANs to communicate, they must route their data through a Layer-3 device (usually a router or a switch).

The simplest analogy, here, would be to imagine that you had two teams that you had to maintain confidentiality within whilst sharing the same physical space. You decided that different languages could achieve this for you - you picked one team who spoke only Swahili whilst picking the other team that only spoke Irish. Result achieved! - both teams can now share the same space and communicate freely but be comfortable that the other team has no idea what they are saying!

The Layer-3 device? Well this is the interpreter who comes into play when, if ever needed, the two teams need to communicate.

vLANs will involve ongoing "per Host" configuration into the future - just as much recruiting new members to the teams, in the example, will always have to consider which language the new recruit will speak.

2. Firewall Segmentation

Placing a firewall between network segments would be analogous to putting the aforementioned teams into separate rooms. Somebody decides when they can open the door and communicate.

Initial setup of the Firewalls can be pretty complex as rules have to be drawn up and implemented to segment internal networks properly. However, once setup, this form of segmentation reduces / eliminates "per Host" configuration goings forward.

3. Software Defined Networking

For the groups in previous example, imagine you had fixed locations for all team members and you could Switch On/Off their ability to actually communicate? Software-Defined Networking (SDN) acts like a smart supervisor who can supervise and control individual members in this manner.

In simple terms, SDN helps create invisible fences (like magic lines) to separate team members in the common area. These fences can appear or disappear whenever needed. So, if one team is having a meeting, they have their own space, and if the other team are doing a different activity, they have a separate space too.

This way, SDN makes it super easy for the supervisor (or network administrator) to organize and control who goes where, making sure everyone has their own space to work and communicate without bumping compromising security requirements. It's like having a dynamic office space with adjustable zones, all thanks to SDN!

Giles' network is "humming along nicely" now - performance has improved dramatically ( we identified and removed several bottlenecks ) and he's a lot more comfortable managing multiple smaller networks than one large (potentially unmanageable) nightmare!

As I left his office, yesterday, he reminded me of the old adage of how you eat an elephant - one bite at a time . . .