Sean of F-Secure has an eye-opening blog post today:
… one of the most interesting things, from our point of view, was [Karsten] Nohl’s brief reference to recent reports (Dec. 13th) about various German police authorities having used nearly half a million “Silent SMS” to track suspects in 2010.
The Federal Ministry of the Interior provided details on December 6th. (PDF)
In the screenshot below, you can see the number of messages sent by three authorities since 2006.
So what exactly does this mean?
Well, basically, various German law enforcement agencies have been “pinging” mobile phones. Such pings only reply whether or not the targeted resource is online or not, just like an IP network ping from a computer would.
But then after making their pings, the agencies have been requesting network logs from mobile network operators. The logs don’t reveal information from the mobile phones themselves, but they can be used to locate the cell towers through which the pings traveled. And thus, can be used to track the mobile targeted.
Read more on F-Secure.
Can law enforcement in the U.S. legally use such silent SMS pings? Anyone know?