"We asked ourselves the question of whether this standard is sufficient to have reliable wiretapping," said Micah Sherr, a post-doctoral researcher at the university and one of the paper's co-authors. Eventually they were able to develop some proof-of-concept attacks that would disrupt devices. According to Sherr, the standard "really didn't consider the case of a wiretap subject who is trying to thwart or confuse the wiretap itself."How to Deny Service to a Federal Wiretap (Thanks, Adam!)
It turns out that the standard sets aside very little bandwidth -- 64K bits per second -- for keeping track of information about phone calls being made on the tapped line. When a wire tap is on, the switch is supposed to set up a 64Kbps Call Data Channel to send this information between the telco and the law enforcement agency doing the wiretap. Normally this channel has more than enough bandwidth for the whole system to work, but if someone tries to flood it with information by making dozens of SMS messages or VoIP (voice over Internet protocol) phone calls simultaneously, the channel could be overwhelmed and simply drop network traffic.
That means that law enforcement could lose records of who was called and when, and possibly miss entire call recordings as well, Sherr said.