Yahoo reveals more details about massive hack

San Francisco

YAHOO provided more details on Wednesday about an epic hack of its services, including that the culprits may have planted software "cookies" for ongoing access to users' accounts.

In revelations that could jeopardise the company's pending US$4.8 billion acquisition by US telecom giant Verizon, the Internet pioneer said it was trying to pin down when it first knew its system had been breached and whether hackers gave themselves a way to get back into accounts whenever they wished.