This is the detection of a potentially unwanted modification (PUM) on the registry that allows the system to see attached files of certain types on Microsoft Outlook as low risk, thus, enabling users to open or execute them without warning. In turn, the “Open File Security Warning” window does not pop up.
The following registry key and entry are added:
Malwarebytes deletes the created registry key without user interaction.
Also, we advise users to do a full system scan as PUM.Optional.LowRiskFileTypes modifications could have been done by malware or PUP.