In the hot seat: A Yahoo spokesman said the company would respond in a timely and appropriate manner to the letter.
WASHINGTON: Six US senators demanded that Yahoo Inc explain why hackers' theft of user information for 500 million accounts two years ago came to light only last week and called the company's handling of the breach "unacceptable."
The lawmakers, all Democrats, said they were "disturbed" that the 2014 intrusion, which was disclosed by the company on Thursday, was detected so long after it occurred.
