2010/3/17 Eric Sandeen <sandeen(a)redhat.com>:
Michał Piotrowski wrote:
> Hi,
>
> I recetly had 30 hours of ssh brute force attack on my system. I'm
> using strong passwords, but still can be geneated from /dev/random, so
> I switched to rsa authentication. What's your favourite way to deal
> with such attacks? Please describe pros and cons.
>
> Regards,
> Michal
Aside from not allowing password logins, I throttle them, they usually
get tired and go away to an easier target.
-A RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport 22 -m limit --limit
1/minute --limit-burst 2 -j ACCEPT
If I understand correctly - this limits ssh connections to two
connections per minute. I tried it before on my devel server without
success. I tried it now with your configuration also without success.
I used
-A INPUT -m state --state NEW -m tcp -p tcp --dport 22 -m limit
--limit 2/minute --limit-burst 2 -j ACCEPT
and I still can connect to ssh as many times as I want.
-Eric
Regards,
Michal