Hacker Chris Paget went ahead with a live demonstration of mobile phone interception at Defcon hacking conference Saturday. Paget was able to intercept mobile-phone data on the GSM networks used by AT&T and T-Mobile. The U.S. Federal Communications Commission had raised questions about his talk. He believes his demonstration was legal because his device was operating in the 900MHz band used by Ham radio devices used by GSM devices in Europe, Paget says. He predicted that every AT&Ts device in the room would connect to his tower, within the next half hour.”]
Source: https://www.csoonline.com/article/2125724/hacker-snoops-on-gsm-cell-phones-in-demo.html