IDS mailing list archives

Re: Changes in IDS Companies?


From: Matt Harris <mdh () unix si edu>
Date: Mon, 28 Oct 2002 09:23:04 -0500

There's also the option of using a non-inline style IDS, but having it
utilize an in-line device which should, theoretically, already be
present on your network border to handle blocking of traffic (such as
router ACL's, which is what Cisco's IDS does by default, or adding and
managing temporary firewall rules, etc).  This seems to work well, and
since the actual IDS work is done on a different host than the network
traffic passing, the actual performance hit is very limited in that you
won't see more of a hit than you will if you were using ACL's or
firewall rules anyways, which most security-concious folk are.  

"A.S.Rajendran" wrote:

There is no single solution for network security.One should use a
combination of all to effectively secure the network.
Both NIDS and Inline IPS method has their particular strengths and weaknesses.
Inline IPS has the ability to block the suspicious traffic. But it has
performance penalties. NIDS cannot effectively block the traffic. But it
will not degrade the network performance. We should use the positive points
of both.
  Inline IPS method should be used to block traffic with protocol anomaly
and to block some suspicious packet temporary by using signatures until
some patch is available to the vulnerable services. NIDS can be used to
monitor all the traffic and generate a log message for all suspicious
packets. HIDS can be used for detecting repeated failed access attempts or
changes to critical system files.
A.S.Rajendran,
Project Leader,
Intoto Software (I) pvt Ltd,
Secunderabad, India.
email: asraj () intotoinc com.
web: www.intotoinc.com

And there
always will be such attacks, furthermore.  Conversely, HIDS has a much
easier time seeing a sudden change to a file that is not supposed to
change, and thus the argument for layers.

Oh, don't get me wrong... I'm all for defense in depth.  And while I agree
that HIDS has some technological advantages over network based IDS, it also
has serious management and cost disadvantages over them as well.  I also
think that network based IDS will close the securtiy gap a lot faster
than HIDS will the management gap.  Cost will probably stay about the same.

Basically, organizations will run network based IDS everywhere and HIDS only
on a few critical systems.  And I think most IDS companies realize this,
which is why everyone hypes their NIDS/NIPS and seems to be putting in a lot
of $$$ into that technology and less so their HIDS.  (I could be wrong about
this one, it's just a gut feeling, I haven't done any studies or anything
like that.)

-- 
/*
 *
 * Matt Harris - Senior UNIX Systems Engineer
 * Smithsonian Institution, OCIO
 *
 */


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