02-18-2014 09:00 AM
Best place would be the HP-UX Porting and Archive Centre. http://hpux.connect.org.uk/
You can download the depot files ready for install or the source code if you wish to compile it yourself.
Looks like they have 6.4 and 6.5 available.
BTW - for reference HP packages OpenSSH into what they call HP-UX Secure Shell. HP's latest version is based on OpenSSH 6.2. https://h20392.www2.hp.com/portal/swdepot/displayP