A Gmail bug allows the from field to be forged so there is no sender listed in the email s header. The trick could be weaponized for phishing attacks that purport to be official warnings or system messages. Developer Tim Cotten, who last week discovered a similar glitch in Gmail, said in a Friday post that a vulnerability in Gmail’s UX allows a hacker to tinker with the From field to forge; and aptly-dubbed ghost emails to be sent.
Source: https://threatpost.com/gmail-glitch-enables-anonymous-messages-in-phishing-attacks/139247/