Telecom cyber resiliency: Lessons from a recent breach

A few months ago, a sophisticated cyberattack quietly rocked the telecom industry in East Asia. The breach, which infiltrated the core network of a major operator, exposed one of the most sensitive components in telecom infrastructure: the Home Subscriber Server (HSS). This system, often described as the digital brain of mobile networks, stores critical user data—particularly from Universal Subscriber Identity Modules (USIMs). Once compromised, the attacker gained potential access to IMSI numbers, authentication keys, SMS metadata, contacts, and more.