Inside the Russian hack of Yahoo: How they did it

In 2014, Russian hackers launched a major data breach on Yahoo by a single employee clicking on a phishing link. This single action allowed hackers access to Yahoo’s network and allowed them to steal a backup copy of their user database containing information on 500 million accounts. They also installed a backdoor to maintain access and used stolen cryptographic data to provide them access to specific user accounts without the need for passwords. They used this ability to monitor over 6,500 accounts — mainly of Russian officials, US government workers, and other high value targets. In 2016, the FBI was able to indict 4 individuals involved in the breach. It later became known that in 2013, a similar breach occurred, allowing access to all 3B user accounts.