RE: IDS\IPS that can handle one Gig

[THolman () toplayer com]

Hi Prashant,

Agreed - with a system based around PCI / Intel architecture (eg Netscreen
IDP, Check Point Interspect/Smart Defense, Cisco 4200, ISS Proventia to name
but a few), then it makes sense to turn off various checks to improve
performance, but at what cost to security?

Is it acceptable to turn off vital security features just because the shiny
new IPS system that you've just bought cannot handle doing too many things
at once?

Of course not!  ...and to be completely brutal, anyone reading this who
comes across such a situation should send this equipment back to the
reseller as being unfit for purpose.  There are plenty of network IPS's that
are designed to do the job in hand with built-in ASIC technology (eg McAfee,
TippingPoint and TopLayer) and offer far more punch for the money.

There are a whole realm of attacks specifically designed to evade IDS/IPS
devices through use of fragments.  The theory being that with fragmented
traffic, an attack can spread itself across multiple packets, which all get
past string search engines that are looking for a complete string, rather
than bits of it.

With an IDS, this isn't a problem - the IDS can sit to one side, observe the
packets coming in, take note once it has seen a stream of fragments and
reassembled them, and quite happily spend a couple of seconds catching up
with other stuff before it sends alerts about any signature matches it finds
in both normal and reassembled traffic.  

However, with an IPS, you're supposed to be analysing network traffic at
line speeds, and you do not have the luxury of hanging around whilst a
machine designed for client/server purposes works out whether or not there's
an attack concealed within fragments.  After all, most fragmented traffic is
genuine traffic - you need to let it through.

Fragmented traffic is a real security threat that needs addressing, and
disabling security measures that take steps to reassemble and verify such
traffic will cause a failure of just about any security audit you throw at
your network, plus leave you open to litigation if your failure to address
such attacks causes a 3rd party loss.

Regards,

Tim


-----Original Message-----
From: Prashant Khandelwal [mailto:prashant () juniper net] 
Sent: 30 May 2005 06:03
To: focus-ids () securityfocus com
Subject: RE: IDS\IPS that can handle one Gig

Adding to this conversation one relevant point would be, Policies which
are pushed on the sensor makes big difference in the performance of the
box. 

E.g.: If Fragmentation and reassembly turned off it can be observed that
box performs better as it does not need to take care of tiny fragmented
packets (In real life having such policies doesn't make any sense).

Over all One should know the Claimed performance figures with avg packet
size ,What type of traffic was used for achieving that particular
performance figure ,What kind of policies were pushed on the sensor.
This can really help to know how a particular IPS can fit in your
network environment.


My 2 cents
Cheers
Prashant 


-----Original Message-----
From: THolman () toplayer com [mailto:THolman () toplayer com] 
Sent: Thursday, May 26, 2005 2:17 PM
To: focus-ids () securityfocus com
Subject: RE: IDS\IPS that can handle one Gig

Hi Randall,

Throughput is unimportant when it comes to choosing an IDS/IPS, and to
be
honest, a bit of a bun fight when you place two vendors side by side and
start scouring their datasheets for practical information.

What is important, however, is the number of packets per second the
device
can process, the maximum number of connections that such a device keeps
state for, and last but not least, the latency that such a device will
introduce into your network if placed inline.

The smaller the packets used in a test, the smaller the performance in
terms
of megabits.  The larger the packets, the bigger the performance in
terms of
megabits.  Unreliable, and totally abused by most vendors on their
datasheets.  It's quite easy to say 'we support 1000 Mbps', only to say
in
small print the average packet size is 595 bytes.  You only need to
search
Google for '1000 Mbps 595 bytes' and you'll soon find out what I mean..
;)

The vendor in question, although claiming Gigabit performance, can only
setup TCP connections at a rate of 5,000 per second - if you do the
math,
you'll soon find out that this represents less that TEN MEGABITS per
second
in 'throughput' terms.

Is it ethical to claim Gigabit performance, only for the potential end
user
to run a number of tests with small packets sizes and find out this is
not
the case?

The moral of the plot is to never trust a datasheet - either thoroughly
test
the products before purchase, or look toward an independent testing
house,
such as NSS (www.nss.co.uk), whom have the resources and experience to
regularly generate test results that count.

At TopLayer, we regularly deploy into Gigabit environments, and
encourage
the customer to test (using Smartbits, Ixia or Spirent) for piece of
mind.
Rest assured, each time they do this, we pass with flying colours, and
this
is what makes us one of the top market leaders in Gigabit IPS solutions.

Regards,

Tim


-----Original Message-----
From: Randall Jarrell [mailto:rgj () msn com] 
Sent: 19 May 2005 16:28
To: focus-ids () securityfocus com
Subject: IDS\IPS that can handle one Gig

Greetings,

We are currently evaluating IDS\IPS vendors. We have tried two vendors,
whom
I will not name unless you ask me, that have made claims that they can
handle a Gig of through put but actually start to fail around the
300-500MB
range.

Could anyone share a success story of a vendor they are using that is
handling this type of traffic?

Thanks in advance,

-RGJ

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