Lieu calls for House probe into mobile security flaw

Rep. Ted Lieu (D-Calif.) has called on Congress to investigate a vulnerability in mobile communications that allows eavesdropping and location tracking.

The hole found by German security researchers in Signaling System No. 7, a common telephony protocol, poses a threat to U.S. national security, Lieu wrote in a letter to Rep. Jason Chaffetz (R-Utah), chairman of the House Oversight and Government Reform Committee. Researchers found the flaw over a year ago but have recently shown that it is still exploitable.

"The applications for this vulnerability are seemingly limitless, from criminals monitoring individual targets to foreign entities conducting economic espionage on American companies to nation-states monitoring U.S. government officials," Lieu wrote.

In a CBS "60 Minutes" segment that aired April 17, reporter Sharyn Alfonsi called Lieu from a commercial mobile phone. Using only the phone number, researchers at Berlin-based Security Research Labs were able to listen in on the call.

Lieu said during the segment that President Barack Obama called him last year on his cell phone. The prospect that someone was eavesdropping on the call is "immensely troubling," Lieu said.

If the flaw turns out to be valuable for intelligence gathering, Lieu said he would call for U.S. intelligence officials who knew about the flaw to be fired.