As cybersecurity becomes a top priority for businesses, microsegmentation is emerging as a key approach to strengthen network protection. Particularly in virtualized environments, such as those used for virtual machines (VMs), microsegmentation allows the network to be segmented into smaller units to control traffic and access better. This article explores the advantages and disadvantages of this technology, particularly in complex environments such as those found in banking sectors.
What is microsegmentation?
Microsegmentation is dividing a network into isolated segments at a granular level, enabling fine-grained management of security policies. Unlike traditional segmentation, which operates at the subnet or VLAN level, microsegmentation operates directly at the level of individual workloads, such as virtual machines (VMs) or containers.
The benefits of microsegmentation
1. Precise access control
One of the most significant benefits of microsegmentation is its fine-grained control over network access. For organisations handling large volumes of sensitive data (as is often the case in banking), the ability to define access policies for each VM, or even for each application, helps reduce the attack surface. If an intruder manages to penetrate the network, restrictions on lateral network traffic prevent threats from spreading to other segments.
2. Limitation of lateral movements
In the event of an access point compromise, micro segmentation limits lateral movement—the ability of an attacker to move through the network from a compromised entry point. By segmenting different services and VMs, threats can be isolated and damage contained.
3. Compliance and audit
The ability to precisely control who accesses which resources and track that access in real-time makes it easier to comply with strict data protection regulations. Additionally, microsegmentation enables the internal data flow auditing, providing greater visibility into regulatory compliance (such as GDPR, PCI-DSS, etc.).
The disadvantages of microsegmentation
1. Increased complexity of architecture
However, one of the main drawbacks of microsegmentation is the architectural complexity it generates. We are far from the “KIS-KIS” architectures ( Keep It Stupid, Keep It Simple ») The more segmented the IT environment is, the more difficult it becomes to manage, especially in massively virtualized environments. Creating and maintaining rules for each VM, each service or each application can lead to an explosion of configurations, requiring in-depth monitoring and expertise.
2. Administrative overload
Implementing and managing a microsegmentation strategy requires significant human and technical resources. The security team must not only define specific rules for each segment but also constantly monitor access and adjust policies based on changes in the architecture.
3. Potential impact on performance
Microsegmentation, while beneficial for security, can introduce some latency, especially if firewall rules are poorly optimised. In banking environments, real-time performance is often required, this latency can become a limiting factor. Therefore, be sure to carefully evaluate the balance between security and performance.
My view on this technology
Over the years, in various projects where IT security was a key concern, particularly in highly regulated environments, I have witnessed the direct impact that a microsegmentation strategy can have on a company’s agility. While this technology is highly effective in protecting sensitive assets and complying with regulatory constraints, it can also slow down the speed of development and increase operational costs.
Microsegmentation is a promising technology that enhances security, especially in sensitive industries like finance. However, it must be implemented cautiously, as it can easily add to the infrastructure burden and lead to higher operational costs. Beyond securing VMs, it is essential to keep in mind the balance between ease of administration and operational efficiency.
In some cases, implementing microsegmentation at scale has led to complex architectures, requiring increased coordination between network, security, and development teams. Without effective management of this complexity, it’s easy to fall into the trap of oversegmentation , which can cripple overall efficiency.
Implementation and available solutions
Microsegmentation implementation can be achieved using various solutions available on the market. Products like VMware NSX, Cisco ACI, or Illumio offer specific features to manage segmentation at the workload level effectively. These tools facilitate the management of security policies while allowing increased visibility into network traffic.
I have personally worked on the Illumio solution, notably in a banking environment, where it has proven its effectiveness in securing VMs and limiting lateral movements. If a customer wishes to implement this technology, the following steps would include an assessment of the existing infrastructure, choosing the most suitable solution, and establishing a migration plan, ensuring strong support from the network and security teams to manage the increasing complexity.
Conclusion
Microsegmentation is a powerful tool for enhancing network security, particularly when controlling access to virtual machines and other critical assets. However, we must be cautious with implementation, considering the increasing complexity of the architecture and performance requirements. A thoughtful balance between security and ease of administration is essential to fully realise the benefits without adding operational burden.
In complex and sensitive environments, such as banking, microsegmentation must be carefully planned and tailored to specific needs to ensure optimal protection while maintaining the flexibility needed for innovation and customer service.