[TriLUG] Removing version banner

[Mike Johnson]

Jeff Bollinger [jeff01 at email.unc.edu] wrote:
> Does anyone know how to remove/change the banner for SSHD, for example,
> instead of having:
> 
> ssh-2.0-openssh_3.0
> 
> I'd like it to say:
> 
> ssh-15.2-openssh_22.6
> 
> Any ideas?  It's not in the banner file (which I haven't created) is it?

First question: why?  You do understand that those numbers are
there for a reason, yes?  That's how ssh negotiates which version
of ssh (v1 or v2) to use.  It has to decide which encryption
schemes to use before it can actually start to use them.

Second question:  after reading the first, are you still sure you
want to do this?

If you -really- want to play with the version numbers, you have to
edit the source code.  Look at version.h.  It's pretty clear
how to change it.

The 'ssh-2.0' part is set by the version of ssh you're using.
It's the part that is used for ssh version negotiation.  You'll
need to leave that alone, for now.

Editing version.h will change the 'openssh_3.0' part.

In the end, what's the reason for changing it?  Setting it to
'openssh_22.6' is -way- obvious to an attacker (if that's
your reason).  You're better off setting it to 3.0.2.  Better
yet, simply upgrade to 3.0.2 (3.0.2p1 is what's current for
Linux).

Mike
-- 
"Yeah it is! Cause he's bakin' in the...kitchen of darkness!  A pie of
lost souls...until it's golden brown!" -- Moltar on Space Ghost