Re: Reverse Shell?

[Jacob S <stormspotter@6Texans.net>]

On Mon, 11 Jul 2005 09:30:19 -0600
bob@proulx.com (Bob Proulx) wrote:

> Jacob S wrote:
> > I have a friend that I'm helping upgrade Debian on their desktop.
> > This friend is not very computer literate - even in Windows. So
> > they're having a problem that I need to troubleshoot, but they're
> > behind a firewall so I can't ssh into their computer.
> > 
> > There are not currently any ports forwarded from the firewall to
> > this computer and we do not have any access to the firewall to
> > enable something like this, either. What I am hoping is that I can
> > have them establish an ssh connection into my firewall with some
> > software that would then allow me to get a shell on their computer.

<snip - good legal disclaimer>
> However if that is difficult, the security issues understood, then you
> can open a tunnel with ssh from their machine to yours.  You could
> follow the tunnel back to their machine and then help them.  Here is
> an example:
> 
>   ssh -N -P -R 2222:$(hostname):22 user@remotehost
> 
> That ssh's into the remote machine and opens a listening connection on
> port 2222.  Connections to that port will be forwarded through the
> tunnel to the local host port 22.  You would give your friend a login
> on your machine (user@remotehost) and they would also give you a login
> on their machine too so that you would be able to log in there.
<snip>
> You would connect to your friend's machine through the tunnel like
> this:
> 
>   ssh -p 2222 localhost

Ah, and we see once again why Debian-user is such a powerful resource...
I hadn't even noticed the -R option for ssh. :-( 

Thanks, Bob, Frank, Steve and Henrik for the useful examples and
explanations. That works beatifully! :-)

Jacob