The Side Door Problem: What the Korean Bank Breaches Mean for US Banks

What happened

Between late September and early October, one operator breached at least seven Korean financial firms in a matter of weeks. They most likely used an open source AI pentest agent. The core payment systems were reportedly untouched. The attacker came in through side systems instead: a loan broker portal, an employee mobile app and a sales support system.

Why it matters

US financial institutions run the same kinds of systems, and most annual pentests never look at them. The budget pays for testing the front door, and compliance scoping leaves the side doors out.

In this session, Kay Kwak explains how these AI-driven attacks work and what signs show one is probing your perimeter. Jeff Martin then applies it to US teams: where your side doors are, why they get scoped out, and how to test them at a cost that makes sense.

You’ll leave with

• Six detection signals that show an AI agent working against your perimeter
• A short list of systems to test first, ranked by where this attack pattern lands
• A clear view of the gap between what your pentest budget covers and what an attacker sees