Attackers can hide ‘external sender’ email warnings with HTML and CSS

The “external sender” warnings shown to email recipients by clients like Microsoft Outlook can be hidden by the sender, as demonstrated by a researcher. Turns out, all it takes for attackers to alter the “external sender” warning, or remove it altogether from emails is just a few lines of HTML and CSS code. […] This post appeared first on Bleeping Computer
Author: Ax Sharma