PORTKnockOut: Data Exfiltration via Port Knocking over UDP

Data Exfiltration is arguably the most important target for a security researcher to identify. The seemingly endless breaches of major corporations are done via channels of various stealth, and an endless array of methods exist to communicate the data to remote endpoints while bypassing Intrusion Detection Systems, Intrusion Prevention Systems, firewalls, and proxies. This research examines a novel way to perform this data exfiltration, utilizing port knocking over User Datagram Protocol. It focuses specifically on the ease at which this can be done, the relatively low signal to noise ratio of the resultant traffic, and the plausible deniability of receiving the exfiltration data. Particular attention is spent on an implemented Proof of Concept, while the complete source code may be found in the Appendix.