Network Segmentation

Most networks used to be built like a single, open floor plan:
once you were inside, you could walk almost anywhere.

Network segmentation changes that.

Network segmentation is the practice of dividing a network into smaller, isolated sections so that users — and attackers — can only access the parts they truly need.

Think of it like a building where:

employees can only enter their own department
sensitive areas require special badges
guests are restricted to the lobby
and high‑value rooms are locked behind multiple doors

Even if someone gets inside, they can’t roam freely.

Digitally, segmentation limits access by:

separating critical servers from general user networks
isolating backups
restricting administrative systems
dividing cloud environments
enforcing access controls between departments
limiting communication between devices

Why this matters for insurance:
Segmentation is one of the most effective ways to reduce the impact of an attack.

It slows or stops:

lateral movement
privilege escalation
ransomware spreading across the network
attackers reaching sensitive data
unauthorized access to backups
large‑scale data exfiltration

When a company says, “The attacker only reached one part of our network,” segmentation is often the reason.

When a company says, “Everything was encrypted,” segmentation is often what was missing.

The takeaway:
Network segmentation limits how far attackers — or even employees — can go.
It reduces the blast radius of any incident and is a core pillar of Zero Trust.

Pop Culture Parallel:
In Jurassic Park, the park’s systems are divided into separate control areas — and when one section goes down, others remain isolated. That’s segmentation: containment through separation.

Real‑World Example:
During the 2017 WannaCry outbreak, organizations with strong segmentation saw limited impact, while flat networks experienced widespread encryption across thousands of machines.

Vocabulary Reinforcement (from earlier posts)

Zero Trust
Lateral Movement
Privilege Escalation
Data Exfiltration
Initial Access
EDR
SIEM
Backups (coming soon)
Least Privilege (coming soon)

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