Alarming Security Defects in SS7, the Global Cellular Network—and How to Fix Them

The global network that transfers calls between mobile phone carriers has security defects that permit hackers and governments to monitor users’ locations and eavesdrop on conversations.

Courtesy ESD America

As more reports of these activities surface, carriers are scrambling to protect customers from a few specific types of attacks.

The network, called Signaling System 7, or SS7, is a digital signaling protocol that mobile phone carriers including AT&T, T-Mobile, and Sprint use to send messages to each other about who is a subscriber, where subscribers are located, and how calls should be routed to reach them.

SS7 began as a closed network shared among a few major mobile phone carriers, but grew porous as more carriers joined. Hackers and governments can now gain access by purchasing rights from a carrier (which many are willing to provide for the right price) or infiltrating computers that already have permission. more

One security firm advises:
"...we have two products that represent the world’s first comprehensive solution against
SS7 attacks: ESD Oversight Protect & ESD Oversight Detect. SS7 Network Penetration testing is
also available to carriers around the world who recognize the need to ensure their networks and their
subscribers are protected from the potential damaged these vulnerabilities expose."

Extra Credit — Ghosts in the Network: SS7 and RF Vulnerabilities in Cellular Networks — a presentation given at RSA Conference 2016