T-Mobile CEO Apologizes for Data Security-Breach

The chief executive of T-Mobile US Inc. apologized to customers for a security breach that has exposed personal data from more than 50 million people and said the wireless company was working to strengthen its cyber defenses.

The Bellevue, Wash., company on Friday said it struck long-term partnerships with cybersecurity firm Mandiant and consulting firm KPMG LLG after the hack of its systems that exposed millions of Social Security numbers, birth dates and other data.

“We didn’t live up to the expectations we have for ourselves to protect our customers,” CEO Mike Sievert wrote in a public letter. “Knowing that we failed to prevent this exposure is one of the hardest parts of this event.”

John Binns, a 21-year-old American who moved to Turkey a few years ago, told The Wall Street Journal he was behind the security breach. He said the company’s lax security eased his path into a cache of T-Mobile records. “Their security is awful,” Mr. Binns told the Journal.

It wasn’t immediately clear whether Mr. Binns worked alone or with help. T-Mobile said Friday the attacker first pierced the company’s testing environments before gaining access to other systems through brute-force attacks and other methods.