Flow-based SSH intrusion detection system (NfSen plugin)
The code currently available on GitHub is what should be v3.0 shortly, but is unstable as of this moment. Please use either v2.4.x from SourceForge, or be aware of a probably very hard time gettings things up and running.
For updates and support, please consider the mailing list (still over at SourceForge) or #sshcure at Freenode.