Nippon Telegraph & Telephone (NTT), the 64th biggest company in the world, according to the Fortune 500 list, has disclosed today a security breach.
NTT says hackers gained access to its internal network and stole information on 621 customers from its communications subsidiary, NTT Communications, the largest telecommunications company in Japan, and one of the biggest worldwide.
The hack took place on May 7, and NTT says it became of the intrusion four days later, on May 11.
The company says hackers breached several layers of its IT infrastructure and reached an internal Active Directory (AD in the graph below) to steal data and then upload it to a remote server. read the rest here