New module: sctp-exfil

[chrisforce1]

SCTP can be used to bypass monitoring and filtering, along the lines of http://0x27.me/ssh/sctp/privacy/security/evasion/2015/07/27/SSH-Over-SCTP/. It's a different protocol than TCP or UDP, and I'd like to do some marketing around this at some point to raise awareness.

In this case, we'd do the following:

• Set up the FTP service from New module: ftp-exfil #23 over SCTP
• Configure the client to use SCTP, establish a session, and send data to the service

We'd want the module to report on success or failure, so that users can see whether SCTP is being blocked within their environment (similar to what we do with Tor, DNS tunneling, etc.)