All users who have Yahoo email, and the owner of the account against other Yahoo services such as Flickr and fantasy sport were affected.
Yahoo said stolen information includes names, email addresses, mobile numbers, birthday dates, up to passwords. In some cases, security questions, as well as answers, are also stolen.
"The investigation shows that the information stolen does not include payment data or information about bank accounts, all of which is stored in a system that we believe is not affected," said a representative from Yahoo.
The company, which has been acquired by Verizon for US $ 4.5 billion, said the discovery was known when it was integrating Yahoo with AOL, one of Verizon's subsidiaries. This also had an impact on Verizon itself.
"Verizon is committed to accountability and transparency and we are proactively working to ensure the safety of all users and networks against cyber-world threats.Our investment at Yahoo gives them the opportunity to continue significant processes in improving security," said Chief Information Security Officer Verizon, Chandra McMahon.
As a form of countermeasures against the burglary action, Yahoo provides direction for users to secure their account. First, change the password and security question along with the answer. Second, notice whether your account is doing any suspicious activity. Then, third, be wary of parties or links trying to ask for personal information. Finally, avoid clicking or downloading from emails that doubt its origin.