STG's FireEye Products buy largely undoes FireEye's $1 billion purchase of Mandiant in December 2013, which brought together FireEye's signatureless web, email, data center, and mobile security platform with Mandiant's endpoint security and incident response. Kevin Mandia founded Mandiant in 2004 and served as FireEye's COO for two-and-a-half years after the deal before becoming CEO in June 2016.