FireEye: Tech firms' secret weapon against disinformation

This week has seen major social media sites step up their policing of online disinformation campaigns.

Google disabled dozens of YouTube channels and other accounts linked to a state-run Iranian broadcaster running a political-influence campaign.

Facebook removed 652 suspicious pages, groups and accounts linked to Russia and Iran.

Twitter took similar action shortly thereafter.

What did they have in common? The security firm FireEye.

Best known for its work on high-profile cyberattacks against companies like Target, FireEye is emerging as a key player in the fight against election interference and propaganda campaigns.