Re: IDS vs. IPS deployment feedback

[Paul Schmehl <pauls () utdallas edu>]

Andrew Plato wrote:
> Number of rules does not equal quality of IDS/IPS technology. 
>
> Or in other words, just because a IDS/IPS has a zillion rules doesn't
> mean those rules are any good. Or that implementing or using that
> technology is good. 
>
> Your 500 number is wrong. When you get into the leading commercial IPSs
> (TippingPoint, ISS, Juniper, McAfee) these products on average have
> 2000-3000 signatures.

I'd be very interested to know how you would know this, since their 
"signatures" are proprietary.  Does TP have a list of their "signatures" 
somewhere that I can look at?  (Trust me, I've asked.)

> However, in some technologies, one signature
> handles an entire class of vulnerabilities. Where Snort needs multiple
> signatures for the same vulnerability, ISS can protect against the
> vulnerability with 1 signature. TP is the same.

Interesting.  I use both snort and TP daily.  Please explain how you 
know this.  Please provide one single example of proof of a single TP 
signature that equals multiple snort signatures yet both cover only the 
exact same vulnerability.

> I don't know Juniper and
> McAfee as well, but I suspect they are similar. 
>
> Snort also has a lot of unique signatures that people have designed for
> highly specialized purposes. That is definitely a benefit to some
> organizations. But, those signatures are only useful in those unique
> situations. And all the commercial products support custom signatures -
> so you can do the same thing for your TP or ISS box. 
Interesting.  Please provide the documentation for custom signatures on 
TP.  I could definitely use them.  (I'm hoping you don't mean the 
fill-in-a-box GUI they provide.  I'm looking for the type of 
customization I can only get with snort.)

> Furthermore, Snort rules are developed by volunteers (or Sourcefire). As
> such, SNORT is usually behind the curve on new signatures. ISS, for
> example, does their own independent security research an has signatures
> to protect against things that Snort people don't even know about.

Interesting.  Please provide an example of where ISS was detecting a 
vulnerability before snort was.

I suspect the folks at VRT would be highly offended by the implication 
that they're not professional enough to recognize vulnerabilities, but 
I'll let them defend themselves.  They're certainly an "independent 
security research" team.

> Other
> vendors buy exploits from the hacker market - again giving them access
> to vulnerabilities long before it hits the public and subsequently the
> people who develop SNORT signatures. 

Ignoring the ethics of funding the hacker market,  please provide proof 
that Sourcefire never knows about vulnerabilities until they hit the public.

> Now, I realize I sound like a ISS or TippingPoint sales person. And yes,
> I have a vested interest in such products because my company sells them.

Have you ever installed snort?  Used it?  Run it side by side with TP? 
Or ISS?  Or both?  Done any comparison tests?

> But, I also know that I've seen more than a few organizations throw away
> Snort-based protections because the administration and management of
> them was too resource intensive. And merely having 5000 signatures
> available does not translate to effective security. 
Really?  I find my snort install much more useful than the TP install 
for tracking down things that don't fit the cookie cutter scenarios that 
most IDSes work with.  One-size-fits-all exploits are a dime a dozen. 
It's the oddballs that should get your attention, but TP doesn't "see" 
those (nor would I want it to.  That's not its purpose.)

Your analysis doesn't strike me as fact-based.  Perhaps you can convince 
me otherwise?
--
Paul Schmehl (pauls () utdallas edu)
Adjunct Information Security Officer
The University of Texas at Dallas
http://www.utdallas.edu/ir/security/

Attachment: smime.p7s
Description: S/MIME Cryptographic Signature