In a Tuesday report, Reuters has revealed that bigwig Internet firm Yahoo built surveillance tools in 2015, in accordance with the secret directive issued by the National Security Agency (NSA) and the Federal Bureau of Investigation (FBI), asking the company to scan the incoming mails of its customers.
According to the Reuters report, based on the information shared by unidentified former Yahoo employees, the NSA and FBI asked Yahoo to search for "a set of characters," which could, for instance, be a phrase or an attachment.
The report has also revealed that since Yahoo CEO Marissa Mayer chose to comply with the NSA and FBI's secret directive, the move prompted Alex Stamos - Yahoo's Chief Information Security Officer at that time - to quit the company in June last year.
Stamos - who is currently the security chief at Facebook - had reportedly told the staff working for him that hackers could potentially gain access to customers' stored emails by exploiting a programming flaw.
Meanwhile, in response to the Reuters report about Yahoo building surveillance tools to scan customers' incoming emails last year, a Yahoo spokesman said in an email: "Yahoo is a law abiding company, and complies with the laws of the United States."