E21 · Woori FIS · Feb 2026 – Oct 2026
A security review that tested requirements with numbers
- Security review
- Network separation
- Microsegmentation
In one line
I handled the security part of a review for adopting a new virtualization platform. I organized the requirements, tested them with numbers, and proposed a split of duties by traffic direction.
Background
I owned the security section of a technical review report for adopting new virtualization infrastructure.
What I did
I organized the security requirements into three areas.
- Common: logical network separation between group companies (a Korean financial regulation), applying existing security solutions, SIEM (centralized security log analysis) integration, and access control for management terminals
- Physical: controls to implement with physical appliances, such as perimeter firewalls
- Logical: controls to implement with platform policy, such as separating tenants (the organizations using the platform) and blocking traffic between them
I tested the requirements with numbers. Comparing the capacity of the platform’s own policy with the required level showed that it could not meet the need.
I proposed a split of duties.
- North-South traffic (between users and servers, outside and inside): physical perimeter firewall
- East-West traffic (between servers, inside): virtualization platform policy
Plain explanationWhat is microsegmentation?
A perimeter firewall sees traffic coming in and going out, but traffic between internal servers never passes through it. To stop an attacker who takes over one server from spreading to the next (lateral movement), you need microsegmentation, which controls traffic at the level of each server.
With only a front-door lock on an apartment building, a burglar who gets in can reach every home. With a lock on each home, the damage stops at one.