“German researchers have discovered security flaws that could let hackers, spies and criminals listen to private phone calls and intercept text messages on a potentially massive scale – even when cellular networks are using the most advanced encryption now available.
The flaws, to be reported at a hacker conference in Hamburg this month, are the latest evidence of widespread insecurity on SS7, the global network that allows the world’s cellular carriers to route calls, texts and other services to each other.”
▻http://www.washingtonpost.com/blogs/the-switch/wp/2014/12/18/german-researchers-discover-a-flaw-that-could-let-anyone-listen-to-y
SS7 is indeed awfully broken but, unlike what happens on the Internet (where everyone knows about the weaknesses of BGP and DNS and work on it), the telco companies were, until now, successful in hiding the problem under the rug.