Re: SSH Brute force attacks

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Cool.  Ive been having the same issue for quite some time.  Im going to look
hard at this.

ddh


Quoting Alistair Tonner <Alistair@xxxxxxxxxx>:

> On May 7, 2005 01:32 am, Taylor, Grant wrote:
> > > One one of my hosted boxes, my logwatch scripts continuously pipe out my
> > > ssh and auth log of unsuccessful dictionary attacks
> > >
> > > I came across this link : http://blog.andrew.net.au/2005/02/17/
> >
> > Not a bad idea, but I think there is a little bit of room for growth.
>
>
> 	Grant:
> 		I think you've put together the basis for a FAQ on recent/TARPIT here --
> and
> I like yer attitude *grin*
>
> 	Oskar A:
>
> 		If you'd like I can buff the following up some, but I think this deserves a
> mention in the iptables tutorial:
>
> >
> > # Let's jump to the SSH_Brute_Force chain if this is a new connection that
> > is not from my IP address. # This will prevent processing these rules for
> > non SSH traffic.
> > iptables -A INPUT -p tcp --dport 22 -m state --state NEW -j SSH_Brute_Force
> > # Let's white list some IP addresses.
> > iptables -A SSH_Brute_Force -s $My_IP_Address -j RETURN
> > iptables -A SSH_Brute_Force -s $My_Friends_IP_Address -j RETURN
> > iptables -A SSH_Brute_Force -s $Any_other_IP_that_I_want_to_white list -j
> > RETURN # If there have not been 4 NEW connection attempts from this source
> > IP address in the last 60 seconds let's return to the INPUT chain. iptables
> > -A SSH_Brute_Force -m recent --name SSH ! --rcheck --seconds 60 -m recent
> > --hitcount 4 --set --name SSH -j RETURN # Well, the NEW connection has been
> > seen so let's update the SSH recent list. iptables -A SSH_Brute_Force -m
> > recent --name SSH --update
> > # I like to log on a line by it's self so I don't have to remember to do it
> > on my last line prior to the end of my script. iptables -A SSH_Brute_Force
> > -j LOG --log-prefix "SSH Brute Force Attempt:  " # Let's send the person
> > that is trying to SSH in to us to the TARPIT target and make them think
> > twice before they try again. # TARPIT will force the site that is SSHing in
> > to us to timeout the connection.  Sure stick you hand in my port, I'll grab
> > hold of it and not let go, # you will have to chew your arm off and grow a
> > new one and try again.  I'll hold your new arm again and again and again
> > and...  This should slow you down. iptables -A SSH_Brute_Force -j TARPIT
> > # I can be a mean vindictive SoB (Sweet Old Buzzard.  NOT!)
>
> 	I like that in an admin. *grin*
>
> 	Alistair Tonner
> >
> > I tried putting in comments to explain the logic of what is going on, if
> > you have any questions please let me know.
> >
> >
> >
> > Grant. . . .
>


--
Dwayne Hottinger
Network Administrator
Harrisonburg City Public Schools


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