Since a couple of months some of my users are receiving mails wherein the attachmensts are replaced with cmd.exe. These files seems be the original windows cmd.exe, VirusTotal does not find any virus in it.
In the beginning all those mails where send by serveral yahoo.fr accounts, mostly from Africa, but now also from other African email domains.
I silently block all those emails, but I have no idea what is going on. As fast google search did not give any clues.
Anyone has an idea what is going on ?
Marc