RE: Deliberately create slow SSH response?



Kevin,

Check out fail2ban at http://sourceforge.net/projects/fail2ban -- it
will scan your logs for invalid access attempts and add iptables
firewall rules to block the offending IP addresses after a configurable
number of attempts.

Richard Wilson
EDS
richard dot wilson at eds dot com

-----Original Message-----
From: listbounce@xxxxxxxxxxxxxxxxx [mailto:listbounce@xxxxxxxxxxxxxxxxx]
On Behalf Of Zembower, Kevin
Sent: Wednesday, July 09, 2008 12:56 PM
To: secureshell@xxxxxxxxxxxxxxxxx
Subject: Deliberately create slow SSH response?

This might seem like a strange question to ask, but is there a way to
deliberately create a slow response to an SSH request? I'm annoyed at
the large number of distributed SSH brute-force attacks on a server I
administer, trying to guess the password for 'root' and other accounts.
I think that my server is pretty secure; doesn't allow root to log in
through SSH, only a restricted number of accounts are allowed SSH
access, with I think pretty good passwords. But still, the attempts
annoy me.

I wouldn't mind if SSH took say 30 seconds to ask me for my password.
This would slow the attempts. Is there any way to configure OpenSSH to
do this? I searched the archives of this group with 'slow' and 'delay'
but didn't come up with anything on this topic. Please point it out to
me if I overlooked anything. In addition, I can limit the number of SSH
connections to 3-5 and still operate okay.

Ultimately, I need this solution for hosts running OpenSSH_3.9p1 under
RHEL ES 4 and OpenSSH_4.3p2 under Debian 'etch' 4.0 and Fedora Core 6.

Thanks in advance for your advice and suggestions.

-Kevin

Kevin Zembower
Internet Services Group manager
Center for Communication Programs
Bloomberg School of Public Health
Johns Hopkins University
111 Market Place, Suite 310
Baltimore, Maryland 21202
410-659-6139