Possibly as many as 760,000 address book entries of 3,400 Android smart phones might have been breached by a malicious app. The information included personal names or phone numbers.
According to NetAgent, an information security company in Tokyo, the app in question is "All Japan Telephone Directory" which claims to be a searchable database of the comprehensive telephone directory from Nippon Telegraph and Telephone Corporation. It had been distributed over Google Play since mid September, but has already been suspended.
The app, once installed on an android smart phone, would acquire all the existing address book information and send it off to a server rented by the app author, where the stolen information would be made public. The app does say it would "use the address book information" on the installation screen, but only in an obscure way. Research by NetAgent showed that more or less 3,400 users have installed this app so far.