RE: Intrusion prevention and dDos protection

["Paul Benedek" <paul.benedek () excis co uk>]

Hi,

Although the analogy is correct and that a well planned DDos attack can
cause you to loose services, there are several things that you can do to
limit the chances of success.

Firstly at your ISP edge you can introduce rate limiting.  By limiting the
amount of certain types of traffic, you can allow for legitimate traffic to
pass.  For example if you have a 2 meg pipe, you can limit the amount of UDP
to half a meg, tcp on port 80 and 443 to 1 meg and half a meg for other
traffic.  If the traffic exceeds these values, you can force the traffic to
be dropped.

If you are explicit with the traffic you are allowing, you can further limit
the effects of a DDOS attack.  For example you can deny all fragmented
traffic and ICMP.  You can specify the hosts and ports that need
connectivity with a high degree of granularity and drop all other traffic.
Furthermore if you implement RFC2827 filtering you can limit the chances of
being used as a DDOS engine yourself.

In most cases a well thought out DMZ and ISP edge can reduce the chances of
a success, however as pointed out, you will not get total protection.  You
may however be able to keep critical services operational at the time of a
DDOS attack.


Regards,

Paul Benedek
Director 
Excis Networks Limited
http://www.excis.co.uk




-----Original Message-----
From: Rob Shein [mailto:shoten () starpower net] 
Sent: 23 August 2003 18:26
To: 'Darren Windham'; focus-ids () securityfocus com
Subject: RE: Intrusion prevention and dDos protection

I would hasten to point out that there isn't anything you can buy that will
give you DDos protection.  While a firewall/IPS is like a security guard at
the entrance to a building to keep bad people out, a DDos attack is like so
many bad people trying to get into the building that they choke the streets
leading up to it; nothing you can put in your building will deal with that
congestion or prevent it.

> -----Original Message-----
> From: Darren Windham [mailto:dwindham () dallastelco org] 
> Sent: Thursday, August 21, 2003 10:17 AM
> To: focus-ids () securityfocus com
> Subject: Intrusion prevention and dDos protection
>
>
> I recently had the chance to meet with the guys over at 
> Melior and talk about their iSecure platform.  Has anyone 
> else taken a look at it?  I was pleasantly suprised at its 
> performance.  I ran most of the common scanners on both Linux 
> and Windows platforms and had no such luck with it.  I can 
> only hope that more products like this make it to the 
> mainstream marketplace.  If you are looking for a IPS/dDos 
> prevention I'd make sure you take a good look at these guys.  
>
> I'd love to hear feedback from others who have looked at this 
> or other similar products.
>
> Check them out at http://www.meliorinc.com
>
> Regards,
>
> Darren Windham 
> Network Administrator, Dallas Telco FCU 
> email: dwindham () dallastelco org <mailto:dwindham () dallastelco org> 
>
>
>
>
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Attend Black Hat Briefings & Training Federal, September 29-30 (Training),
October 1-2 (Briefings) in Tysons Corner, VA; the world’s premier 
technical IT security event.  Modeled after the famous Black Hat event in 
Las Vegas! 6 tracks, 12 training sessions, top speakers and sponsors.  
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---------------------------------------------------------------------------
Attend Black Hat Briefings & Training Federal, September 29-30 (Training), October 1-2 (Briefings) in Tysons Corner, 
VA; the world’s premier
technical IT security event.  Modeled after the famous Black Hat event in
Las Vegas! 6 tracks, 12 training sessions, top speakers and sponsors.
Symanetc is the Diamond sponsor.  Early-bird registration ends September 6 Visit: www.blackhat.com
---------------------------------------------------------------------------