Re: is ssh tunneling a security risk?

My experience...

The ssh tunnel will allow you to bypass the web filters and
download all the viruses and trojans without being noticed,
until your machine sends out a million spam emails, and the
IT guys notice it.

Unfortunately I'm the IT guy, so I have to spend half a day
fixing the machine.

On Fri, Oct 17, 2008 at 05:23:19PM +0200, David M. Kaplan wrote:

My IT department is really heavy on security. From outside the
building, they have a rather complex system setup so that you can get
around the firewall and ssh into a single machine. From there, you have
to ssh into the machine you want to use.

To simplify things, I have been using a tunnel to hop from my machine
directly (through the tunnel) to the machine I want to use in the
building. This has worked fine until a couple of days ago when IT
decided to prohibit tunneling for "security reasons" (attempting to use
the tunnel now responds with "channel 3: open failed: administratively
prohibited: open failed"). This has made it almost impossible to work
with the system.

What I am wondering is exactly what "security risk" does an ssh tunnel
pose? I thought you used an ssh tunnel to enhance security, not the
other way around. Can someone give me a reason why it is a risk to
leave this open or give me good arguments that I can forward to IT for
why they should not prohibit tunneling?


David M. Kaplan
Charge de Recherche 1
Institut de Recherche pour le Developpement
Centre de Recherche Halieutique Mediterraneenne et Tropicale
av. Jean Monnet
B.P. 171
34203 Sete cedex

Phone: +33 (0)4 99 57 32 27
Fax: +33 (0)4 99 57 32 95