The most famous opensource implementation for SSH OpenSSH doesn't seem to support VxWorks directly and as far as Google Search, there are no positive replies for "porting OpenSSH to VxWorks".
Is anyone here aware of a good opensource implementation of SSH Server Library for VxWorks?
Starting with vxWorks 6.5, an SSH server is included in vxWorks.
For earlier versions, you might have to do your own port.