The hacking group TeaMp0isoN claims to have compromised Web servers used by T-Mobile. The group took responsibility for the attack, which targeted a Web server that hosted part of the company s Web page, including its media relations information. User names, e-mail addresses, phone numbers and passwords for around 80 staff were also posted, including what appear to be a dispiriting number of default passwords. The attack appears to have been designed to reveal weak security practices at the prominent telecommunications company.
Source: https://threatpost.com/update-hacking-group-teamp0ison-claims-breach-t-mobile-011612/76102/