In the world of BYOD and IoT, we are able to open files on any number of device types. You are most likely aware that opening files and attachments on any device without the proper security in place can put you and your company at serious risk, but how do you know which files potentially are malicious? This paper discusses some of the most common malicious file types that are being used by adversaries to infiltrate your organization as well as the steps you can take to mitigate these risks.