The hacker modifies the baseband processor on some Motorola phones and tricking some older 2G GSM networks into not delivering calls and messages. The hack could shut down some small localised mobile networks by spying on the messages sent from phone towers and not delivering them.
Kévin Redon, a Berlin-based telecommunications researcher said that the hacked firmware, named OsmocomBB, can block some calls and messages by responding to them before the phones that were initially intended to receive them do. The researchers added their OsmocomBB baseband processor runs a simple version of the GSM stack to two different Motorola phones, the C123 and the C118, to observe on air traffic and respond to specific paging requests, or calls.
The trio claims it’s possible to perform targeted denial of service attacks against single subscribers and as well against large geographical regions within a metropolitan area. The trio was able to carry out the attack on a variety of German mobile phone operators including O2, Vodaphone, T-Mobile and E-Plus.