It's not certain what the malware writers were hoping to accomplish, although the code trash-talks Cisco's own SourceFire security hardware. This was likely aimed at specific targets rather than a carpet bombing campaign.

The good news? You probably won't run into this. The malware is currently distributed in specially coded Word documents, and Cisco recently launched a product (Umbrella) specifically designed to counter DNS-based attacks like this. Even so, this shows just how stealthy attacks can get -- and when individuals don't usually have access to corporate tools like Umbrella, you'll still have to be extra-careful about the Word files you receive online.