IDS mailing list archives

Re: Cisco CTR


From: Martin Roesch <roesch () sourcefire com>
Date: Wed, 19 Nov 2003 14:07:55 -0500

On Nov 19, 2003, at 1:32 PM, Renaud Deraison wrote:

On Mon, Nov 17, 2003 at 05:40:30PM -0500, Martin Roesch wrote:
You can infer a number of interesting things from looking at MAC
addresses, hop data, peer information and so on.  In the general case
the information will be accurate, in some cases it will not, it's still
interesting and useful for certain applications.

The map you get is mostly inaccurate in terms of network _topology_.
Have a look at the screenshot on your website - it basically shows
that groups of hosts are <N> hops away, and that your router actually
has two NICs. It looks very nice, though.

Actually you're wrong, it demonstrates topology very well from the viewpoint of a passive system that needs to know basic things like hop counts in order to have an accurate way to gauge the impact of TTL variations in passively acquired packet sets (e.g. NIDS). You're also wrong that we can't determine topology, RNA is capable of discovering topology explicitly by identifying routers, switches, proxies, NATs and so on. Additionally, you're wrong in your interpretation of our network topology that's displayed in our 3D visualizer (which is an easy mistake to make seeing as you have no idea what our network looks like), what it's actually displaying is our dual redundant T1s going out to the internet through our redundant routers and the hosts beyond clustered by hop counts. We can display clusters of data in other ways as well, but this particular view is useful for the sake of screenshots.

I don't doubt that you can do similar things with Nevo, it just seems
that the emphasis and focus of your product is in a different direction
than ours.  If that's not the case I'm sure that everyone here would
enjoy being enlightened as to what you guys are up to with your
product.

You are absolutely right - NeVO is a passive vulnerability scanner, with
all what it implies (get the list of open ports, guess the operating
system, determine who is talking to who, and finally show the list of
vulnerabilities we actually think are vulnerabilities).
Ie, to paraphrase the marketing about RNA :

        . Network Asset Profiles
        . Asset Behavioral Profiles (with Lightning)
        . Security Vulnerabilities
        . Change Events (with Lightning)

Well then it would appear that the difference is that we don't need a separate product to do 50% of the job, we're capable of building pictures of change events, quite possibly at a different level of granularity, with a single device and coordinating that with the rest of our NIDS+Management solution on the back end. Our RNA appliances are fully capable of running stand alone as well as in a distributed mode with the Sourcefire Management Console coordinating and correlating data from multiple sensors.

Note that for security vulnerabilties, we actually consider that people
do sometimes apply patches, so we don't just do an OS lookup in a
vulnerability database to report all the flaws that ever happened for that
particular OS release.

Nor do we.

This is prone to false negatives but this is how we
market NeVO - it's a tool to "get the temperature" of the security of a
network, not to get a list of all the hypothetical flaws that might eventually
be on the network.

Getting a list of the vulnerabilities that exist in an environment only has a few uses such as improving the quality of the information coming out of the NIDS by qualifying events. That is only one of the subfunctions of RNA, our primary thrust with this product lies in asset management and change analysis, it sounds like we have implemented similar technologies with different concentrations and overall goals.

I hope this clear things up,

As do I.

    -Marty

--
Martin Roesch - Founder/CTO, Sourcefire Inc. - (410)290-1616
Sourcefire: Snort-based Enterprise Intrusion Detection Infrastructure
roesch () sourcefire com - http://www.sourcefire.com
Snort: Open Source Network IDS - http://www.snort.org


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