Segmentation Often Starts Broad — But Rarely Goes Deep Enough
One of the most common patterns we see in cloud security architecture is an early reliance on broad segmentation primitives, things like cloud accounts, VPCs (Virtual Private Cloud), subnets, and IAM (Identity and Access Management) boundaries. These are important controls. Account-level isolation is useful for separating dev and prod environments, and subnets help organize networks logically. But too often, that’s where segmentation stops.
The assumption is that separating workloads by account or network segment is enough to contain risk. In reality, most of the lateral movement risk exists inside those boundaries, between the workloads, containers, services, and applications that live in the same trust zone. Once an attacker gains a foothold, via a misconfigured role or a vulnerable workload, what’s stopping them from moving sideways?
That’s where microsegmentation comes in, the control that’s closest to your actual workloads, and the part that’s critical for enforcing zero trust across internal service communications.
Cloud Teams Move Fast, Security Often Misses the First Step
Another challenge we see regularly: segmentation wasn’t part of the original cloud design, not because it was ignored, but because infrastructure teams often build and deploy first, and security comes in later. That’s a shift from the datacenter model, where firewall and routing changes had to go through security before anything could launch.
In cloud environments, infrastructure is code. Engineering teams can spin up entire environments; accounts, VPCs, compute nodes and databases without waiting on tickets or approvals. This flexibility is great for speed, but it often means workloads are deployed into flat, permissive networks with little internal restriction.
In practice, application teams typically end up owning the security groups. That’s not a security decision, it’s a byproduct of how cloud services are orchestrated. Network rules are often embedded into Terraform, CloudFormation, or Kubernetes manifests. The people deploying workloads are the ones defining connectivity, even if they don’t have a security background.
Because of that, it shouldn’t come as a surprise that across architectural assessments, it’s common to find information systems violating approved communication boundaries or worse, wide-open east-west access, where any workload in the VPC can talk to any other workload. This kind of internal exposure creates ideal conditions for attackers: once inside, they can move laterally with ease, often without triggering any alert.
To mitigate this, our security team tried to bring structure to the chaos by centrally managing security groups. We built automation that defined and enforced allowed IPs and ports across environments. It gave us consistency, repeatability, and visibility into what was supposed to happen. But over time, we realized we hadn’t actually solved the root problem. We were still manually reviewing app team requests, still fielding exceptions, and still lacking context-aware enforcement. In many ways, we had just automated the bottleneck.
What Is Microsegmentation and Why It Works in the Cloud
Microsegmentation is the practice of defining and enforcing fine-grained communication policies between workloads, containers, and services, not just based on static IPs, but also on metadata like tags, identities, application roles, or environment.
In contrast to perimeter firewalls or flat security groups, microsegmentation lets you declare intent-based policies like:
“Allow production workloads labeled app=web to connect to app=api on port 443.”
These rules adapt automatically as resources scale, move, or get replaced. They don’t rely on IP mappings or tightly coupled infrastructure logic.
Enforcement typically happens via lightweight agents or kernel-level controls on the workloads themselves. Some systems passively monitor traffic to build behavior baselines; others can actively block unauthorized communication. The key is that enforcement happens as close to the workload as possible, regardless of the underlying cloud provider or region.
Flat Networks Invite Lateral Movement
A common misstep is assuming that workloads in the same subnet, cluster, or VPC are safe to talk to one another. But the reality is: if you don’t explicitly deny it, it’s probably allowed. And once an attacker compromises one system, they’ll try to move laterally, scanning the environment, abusing identity permissions, or reaching adjacent services.
We’ve seen scenarios where a dev workload could reach production data, or where containers in one namespace could talk to backend services that had nothing to do with their function. Microsegmentation helps solve this by enforcing intentional communication paths, closing off anything that isn’t explicitly permitted.
Technical Layers Behind Microsegmentation
Most modern implementations rely on:
- Attribute-based policies: Built using tags, labels, identity claims, or other metadata that reflect application context.
- Distributed enforcement: Agents or sidecars run on workloads and enforce policies at the OS or network layer.
- Traffic mapping and baselining: Tools analyze communication patterns to suggest or auto-generate segmentation policies based on observed behavior.
This makes it possible to apply zero trust principles inside your cloud, where trust is explicitly granted, never implied by network proximity.
Microsegmentation Is Not Optional
Segmentation shouldn’t end at the account or VPC level. If you stop there, you’ve left the hardest part of the problem unsolved. Most cloud breaches don’t happen because someone jumped from one account to another, they happen because of over-permissive internal networks, unmonitored service communications, or flat east-west traffic paths.
Microsegmentation allows you to reduce lateral movement risk, enforce workload-level policies, and adopt a scalable, cloud-native security posture. If it wasn’t built in from the start, it’s not too late to make it part of your architecture now.
Don’t leave your cloud environments exposed. CyberOne helps organizations enforce zero trust with microsegmentation. Reach out to get started!