A network security computing system includes a steganographic communications analysis engine monitoring incoming and outgoing messages on a secure computing network. The steganographic communications analysis engine identifies a pattern of file transfers between a first computing device on the secure computing network and an internal or external message recipient. When a pattern is identified, the steganographic communications analysis engine quarantines an associated computing device from the secure network. The steganographic communications analysis engine analyzes files transferred between the computing device and the recipient for indications of steganographic information and causes display, based on an identified indication of steganography, an indication that the computing device had been compromised by command and control malware.