detection icon

Short bio

PUM.Optional.LowRiskFileTypes is Malwarebytes’ detection name for a potentially unwanted modification (PUM)in the Windows registry where the system is allowed 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.

System modification

The following registry key and entry are added:UnderHKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\PoliciesKey:AssociationsEntry:LowRiskFileTypes=*.exe;*


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.

Add an exclusion

When a Potentially Unwanted Modification (PUM)is detected on your computer, Malwarebytes for Windowsdoes not know whether it was authorized. Optimization software, malware, and Potentially Unwanted Programs (PUPs) are known to make these types of changes, hence they are regarded as potentially unwanted by design.To have Malwarebytes for Windowsignore a PUM, you must add the PUM to the Allow list. Here’s how to do it.

  1. When a PUM appears in the list of Scan results.
  2. Uncheck the entry or entries related to the PUM.
  3. Then click on Next.
  4. You will see a prompt giving you several options.
  5. Choosing Always ignore will add the PUM to the Allow List.
  6. You can remove them there when you decide they should no longer be ignored.
  7. When the PUM is on the Allow list it will no longer show up in your Scan results.