Microsegmentation

Posted on Apr 12, 2024 by

 56

What Is Microsegmentation?

Microsegmentation is a security isolation technology employed within data centers (DCs) to categorize DC services according to specific criteria and establish policies between these categories for traffic management. Traditionally, DCs have been divided into subnets using coarse-grained methods such as VLAN IDs or VXLAN Network Identifiers (VNIs). However, microsegmentation offers a more refined and flexible approach by allowing grouping based on factors like IP addresses, MAC addresses, and VM names. This enables the creation of finer security zones for precise service isolation, thereby bolstering network security.

What Is Microsegmentation?

Types of Microsegmentation

Organizations may opt to deploy various types of microsegmentation depending on their specific requirements and objectives. Common types of microsegmentation include:

Application Segmentation:

Application segmentation safeguards individual applications by implementing security policies that govern access to particular application resources such as databases, APIs, and web servers. This measure helps prevent unauthorized access and data breaches while enabling organizations to enforce least privileged access controls, ensuring that users and applications only have access to the resources essential for their designated functions.

Tier Segmentation:

Tier segmentation focuses on securing different tiers or layers within an application stack, such as the web tier, application tier, and database tier. By doing so, it inhibits lateral movement within the application stack, thereby thwarting attempts by attackers to access sensitive data or resources.

Environmental Segmentation:

Environmental segmentation involves securing distinct environments or zones within a network, such as development, testing, and production environments. This practice enables organizations to impose stringent access controls on these environments, ensuring that sensitive data and resources are exclusively accessible to authorized users and applications.

Container Segmentation:

Container segmentation aims to secure individual containers or groups of containers within a containerized environment. By implementing this measure, the attack surface is reduced, and the likelihood of attackers laterally moving within the container environment is mitigated. Failure to properly segment containers can potentially lead to security vulnerabilities, as containers may access each other's data and configuration files.

Why Microsegmentation?

In traditional data center networks, internal traffic is typically regarded as secure while external traffic is seen as insecure. Consequently, firewalls are typically deployed at the data center network perimeter to inspect and manage traffic entering and leaving the network (referred to as north-south traffic). The technology responsible for analyzing traffic on these border devices is commonly known as border security technology.

However, with the increasing proliferation of data storage and applications, the predominant traffic within data center networks has shifted from north-south traffic to east-west traffic. Consequently, effective security controls for internal traffic become imperative. Incidents where attacks penetrate the network perimeter pose significant security risks to data center networks, potentially allowing attackers to indiscriminately target services within the network. Therefore, cloud-based data centers require robust protection mechanisms for both internal and external traffic.

Routing all traffic between virtual machines (VMs) within a data center through a centralized firewall can hinder the flexibility, distribution, and scalability of the data center. This approach may also lead to performance bottlenecks and capacity expansion constraints.

Microsegmentation offers a more granular approach compared to traditional subnets. It involves partitioning the internal network of a data center and applying security policies to regulate traffic between these partitions or groups. This enables precise control over service policies, limiting the lateral spread of network attacks and bolstering overall security.

How Does Microsegmentation Work?

Microsegmentation organizes data center (DC) services into groups based on predefined rules centered around the concept of security zones. It enforces traffic management through policies governing interactions between these groups. This approach enables fine-grained isolation between groups, which is established based on the following elements:

Endpoint Group (EPG): A collection of entities responsible for delivering services, such as servers and virtual machines (VMs). EPGs can be configured according to various identifiers including IP addresses, MAC addresses, VM names, and applications.
Group-Based Policy (GBP): Policies dictating traffic control within an EPG and between different EPGs.

EPG/GBP implementation

Benefits of Microsegmentation

Reduced attack surface:

By breaking down the network into smaller segments, microsegmentation reduces the attack surface and makes it more difficult for attackers to gain access to critical assets.

Enhanced precision and adaptability in security isolation:

Microsegmentation allows for the establishment of groups using specific IP addresses, MAC addresses, and VM names, thereby facilitating a more precise and adaptable delineation of security zones.

Distributed security:

The microsegmentation solution employs distributed security controls, with service traffic filtered at nearby access switches. As a result, there's no requirement to route east-west traffic centrally through the firewall for security isolation. This approach minimizes network bandwidth usage and mitigates the risk of the centralized control point becoming a bottleneck for traffic.

Enhanced regulatory compliance:

Numerous regulatory frameworks mandate organizations to enforce robust access controls and security protocols for safeguarding sensitive data. Microsegmentation plays a pivotal role in meeting these requirements by restricting access to sensitive resources solely to authorized users and applications. This ensures alignment with regulatory standards and facilitates compliance demonstration by organizations.

Microsegmentation vs. VLAN, ACL, and Firewall

Network segmentation isn't a novel technology. Traditional networks rely on firewalls, VLANs, and access control lists (ACLs) to segregate service traffic. Nonetheless, these technologies exhibit certain limitations:

VLANs are designed to isolate services based on subnets and are incapable of isolating servers within the same subnet.
While ACLs can be configured to isolate servers, the vast number of servers within a data center network necessitates a correspondingly large number of ACL rules. This results in complex configuration and maintenance, compounded by the limited ACL resources of network devices, which fail to meet the demands for deploying numerous ACL rules.
Typically, firewalls are only deployed at the data center's perimeter connecting to external networks. While it's possible to deploy firewalls on each interconnection node within a data center for internal isolation, this entails a substantial investment in hardware and imposes significant configuration and maintenance overheads.

This is where microsegmentation comes into play.

Microsegmentation facilitates finer-grained segmentation, such as segmentation based on IP addresses, IP network segments, MAC addresses, and VM names.
It partitions a network into multiple segments according to predefined grouping rules and enforces policies to regulate traffic between these segments. Consequently, data packets can only traverse between specific nodes.

Microsegmentation