2011 MTS — 1.6M subscriber records leaked
Data compromised
Names, phones, addresses, passport data
Technical writeup
Personal data of 1.6 million MTS mobile subscribers leaked online, posted on Zhiltsy.net. Included names, phone numbers, addresses, passport data for St. Petersburg and Bashkortostan. Database dated to 2006; MTS claimed most numbers no longer valid.
Root cause
Data leak; possible law enforcement source