Shamoon is a Trojan virus that works by infiltrating PCs running on Windows OS and then attempts to cover its tracks. After stealing files, it cripples through the victim’s computer. As a result, the files will no longer be usable.
Shamoon malware has been used in targeted assaults. It purportedly aimed at specific firms or individuals, including at least one in the energy sector. This malware relies in on a one-two punch. Before it spreads to other PCs on an organization’s network, it takes control of an online system (a system that is connected to the Internet). This is according to an Australian news website. — The Droid Guy
Makaseh would allow files from known and authorized contacts only into a PC.