The attack was covered by Chief Security Officer Joe Sullivan and his men forced Uber to dismiss the executive and one of his subordinates this week.
Uber reportedly paid a ransom to hackers US $ 100 thousand for them to remove the stolen data and not to tell the occurrence of the attack on the media or the regulator.
"This should not happen, and I will not make excuses," said Uber CEO Dara Khosrowshahi, who replaced Kalanick in September. "We will change the way we do business."
Uber reportedly refused to identify the attacker. In this attack the hackers managed to get names, email addresses and mobile numbers from more than 50 million Uber users in the world. Meanwhile, for 7 million Uber riders, in addition to that information their stolen data is the SIM number.
At the time of the attack, Uber was talking to the US regulators over other privacy violations and had just finished discussing the issue of how to handle consumer data at the Federal Trade Commission (FTC).
All this encourages Sullivan to cover up the attack in order to avoid new problems. The hack was discovered after Uber's board of directors conducted an investigation into Sullivan's team last month.