[Snort-users] Naming convention of Snort

Erek Adams erek at ...577...
Wed Mar 13 11:56:03 EST 2002

On Wed, 13 Mar 2002, Jason Hammerschmidt wrote:

> So then what's the difference between a HIDS in promiscous mode (with
> tap/mirroring/etc), and a NIDS,

Well, Chris sums it up fairly well with this:

> > Host Based IDS generally refers to monitoring Host based events such
> > as process activity or the like.

To me, that means I can have a HIDS on a machine with no ethernet connection.
Granted, that's not going to happen very often, but it could.  :)

> furthermore using a tap/mirroring
> you're in effect trusting your networking gear to do a lot of things...
> trusting it to follow IEEE 802.x standards (and how often have we seen
> this violated?), trusting it not to fail in even the slightest way,
> trusting it to handle congestion (what if packets get dropped on your
> mirrored port), trusting the software of the switch.  You're not
> garanteed 100% of your network traffic, or at least you can't be
> certain 100% is getting through.  In paranoid circles wouldn't GIDS be
> the only true 100% NIDS?  I've been taught never to trust port
> mirroring/VLAN's/all that jazz of switches if your intention is to be
> highly secure.  I believe there's even something in the FAQ in length
> about the various traps of setting up Ethernet taps/mirroring.  In my
> opinion you cannot trust such setups for intention of a NIDS.

IMHO, if you use just _one_ IDS, you're asking for trouble.  Single point of
failure and all that happiness.  Be safe, spread it out.  Multiple IDS's of
various flavors.  Sure, it's a PITA to maintain, but it gives you the best
"view".  Just remember that there is no 'silver bullet'.  That goes for
IDS's, switches, taps, etc.  It's all the same...

> PS. I'm only asking these questions as a semantics inquiry, I'm not
> meaning to start any wars.  Just feeding my curiosity.

I'm sorry, this isn't an all you can eat buffet.  You'll have to order from
the menu sir.  ;-)

[Note to self:  Cut back a bit on the coffee or start drinking decaf.

Erek Adams

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