The data, associated with at least 500 million user accounts, stolen could be ranked as the largest security breach ever from a single organization. The tech giant said that the attack was done by a "state-sponsored actor" because of its resemblance to previous massive hacks.
Yahoo! Inc. released a statement, "Based on the ongoing investigation, we believe that information of at least 500 million user accounts stolen by hackers was connected in late 2014. We are working thoroughly with the authorities on this matter."
This gives the hackers an access to a wealth of sensitive information from its half a billion users. Information may include names, email address, birth dates, and scrambled passwords, along with encrypted or unencrypted security questions/answers. But Bob Lord, Yahoo's chief information security officer said that it appeared that looted data did not obtain unprotected passwords or information associated with payments or bank accounts because they are stored on a separate system.
Yahoo advised the affected users to change their passwords, change security question information and review account for any suspicious activity. They also recommended to do the same for those who hasn't done since 2014 as an early precaution.
In previous months, the US internet giant received a report from a security researcher that a pseudonymous hacker called "Peace" offered to sell 280 million user account data on the black market.
This online issue really gives Yahoo the worst and difficult timing, as this major theft comes two months after Yahoo signed a deal to sell its internet business to telecom giant Verizon Communications Inc. for $4.8 billion cash, ending a once most powerful tech companies in Silicon Valley. Verizon said in a statement, "We are reviewing the new information as the investigation continues and no details yet if this cyber breach could impact the closing of the deal or the price agreed with Yahoo. We were by Yahoo within the last two days."
This Yahoo-reported hack breaks the official and the current largest breach from Myspace hack, with 360 million users affected just earlier this year and the attack in eBay Inc.