Edward Snowden claims that NSA and GCHQ have managed to break the networks of Gemalto, the largest SIM card manufacturer in the world. With this hack they gained access to the encryption keys of the cards.
The hack as mentioned above was conducted by an NSA and GCHQ team. The information on the attack is revealed by a document from 2010 from GCHQ.
Gemalto manufactures SIM cards for AT&T, T-Mobile, Verizon, Sprint and many more. In total, it manufactures cards for approximately 450 telecommunications providers worldwide.
According to his leak Edward Snowden, stolen encryption keys allow secret services to monitor unlicensed mobile communications from phone companies. They also overshoot the need for a warrant and intercept without leaving traces that can be detected by wireless providers.
Gemalto, for her part, says she did not know about the hack until it was published by Intercept.
"I'm very upset and worried about what has happened," said Paul Beverly, Gemalto 's executive vice president. "What I want you to understand is what kind of impact it will have on any of our customers."