On 10/15/2010 7:34 AM, Michael Scheidell wrote:
>   On 10/15/10 6:52 AM, Tony Graziano wrote:
>> I am hardened and had no issues. I just found the fact that it is a real
>> domain with sip on a subdomain that is not published ANYWHERE until a few
>> hours before the attack, which was very limited since I had cps throttled in
>> a way that Mitigated it gracefully, which was all in another post.
> I would love to get those patches that allow me to use a different port
> for sip url calls!
> No, it doesn't solve the problem, but will cut down on it.
> Your firewall can 'tarpit' anyone (except your ITSP) who hits port 5060
> once you have the ports swapped.
> Tarpitting can effectively slow the attack down, limiting the bandwidth
> the attacker can use.
> Another idea taken from anti-spam systems is the concept of a 'siptrap'
> (like a spam trap). Someone hits sip:[email protected] and our sip
> system 'pretends' to talk to him.
> We might start reporting these ip addresses to dshield.org. The
> combination of posts here, and data collected by dshield.org assisted a
> couple of security researchers in justifying tracking the Amazon EC2
> Cloud ip addresses which were extensively used in sipvicious attacks a
> while back. Amazon saw the correlation and put measures in place to stop
> the abuse of their network. (I wonder: someone uses the Amazon cloud to
> look for open sip servers in order to commit toll fraud.. I but they
> used their own credit card to pay for you, what do you think?)
>
> Anyway, a collective way to track and maybe block these folks who are
> doing this would add to a 'defense in depth' approach to the problem.

I like what you are saying Michael.  I believe sipx should have the same 
type of hooks that any public internet service has like postfix, apache 
and ssh.  A couple of things that come to mind for SIPx:
-a better logging of registration or call attempts that fail, so that we 
can use tools like fail2ban to take the appropriate action.
-maybe a delayed response back when the registration user/password or 
extension are wrong, like ssh
-I like the dshield.org idea, I guess that is similar to the dns 
blacklist lookups that email servers use.
-- 
Regards
--------------------------------------
Gerald Drouillard
Technology Architect
Drouillard & Associates, Inc.
http://www.Drouillard.biz
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