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From: dany allard (dallardalterna.com)
Date: Tue Jan 09 2001 - 09:52:32 CST
Yes an IDS will not detect everything.
What it does detect should be usefull and give you an idea of how many people are
looking at your network.
I recommend "snort" for a network IDS and "tripwire" for a local machine IDS.
Logwatch is also a good program to have installed on your local machines.
Thomas Biege wrote:
> On Tue, 9 Jan 2001, Nix wrote:
> > At 09:25 PM 6/01/2001 +0000, you wrote:
> > >Thomas,
> > >Can you advice us a IDS that dont suck?
> > >I just use Linux at home so I'll probably keep using many things that suck,
> > >at least for try to learning how they suck, but others may need to know
> > >other IDS apps, for corporate use.
> > >http://website.lineone.net/~offthecuff/HIDS.htm
> > >(http://www.networkintrusion.co.uk)
> > >
> > >btw ... also many commercial stuff suck, in this case vulnerability
> > >scanners: http://www.nwc.com/1201/1201f1b1.html
> > IMHO IDS systems are close to worthless. At best they lets you know that you
> > have already been broken into
> That's what a IDS is designed for. For preventing intrusions
> you have to patch your system and have a good security
> Often pattern matching network based IDS are not that usefull,
> because they just detect attacks, that could be avoided by
> a packetfilter and a good administrator.
> NIDS, that use statistical methods or strict-misuse detection
> (mjr called it buglar alarm detection, AFAIK) may also be able to
> provide information about unknown attacks, but they produce
> to much false alarms.
> Encrypted network traffic is bad for the old sensor (promisc
> interface) based NIDS approach (these IDS are nevertheless able
> to detect malicious packet header), but network node NIDS
> (every host has a agent, that reads the unencrypted data from
> the stack above the encryption layer) are able to read
> network traffic, that is encrypted by IPSec or other
> VPN technologies. Unfortunately application layer encryption,
> like SSH, couldn't still be read.
> Host based IDS don't have these limitations. Most of the
> time they analyse log files, syscalls and access to system objects
> (Solaris: BSM Logging, AIX: Audit Logging, NT: Event Logging (?))
> They are also able to see attacks, that happen on the console
> or over a dial-in/serial tty.
> There are some more pros and cons I don't want to discuss.
> But I think it's better to have a IDS, then not to.
> I think a IDS is just worthless, if you buy one, that
> isn't able to fit our needs and if you don't know
> the strong and weak parts of you product.
> If you have a pattern matching ID system, then keep your
> rule/pattern database up to date or it will become worthless
> > at worst, they breed a dangerous false sense of
> > security.
> That's not the fault of the IDS. :-)
> > As a greater percentage of network traffic is being encrypted every day,
> > and an IDS
> > cannot "see" into encrypted traffic, it means that your IDS has a huge
> > blind-spot.
> see above.
> > This is only going to get worse.
> > Test out any of the IIS exploits if you don't believe me (the unicode
> > exploit is a good
> > example because it works against IIS4 and IIS5) this exploit will sail
> > straight past your
> > IDS without raising a murmur, allow you to execute arbitrary programs on
> > the target
> > machine, and even download the servers Private SSL key. FUN!
> Hiding attacks for IDS remebers me of hiding virus code for
> virus scanners. It's the old game on another level.
> Pattern matching IDS are worthless aginst people w/ a little
> skill, that's true. But what if you run IIS in a sandbox
> to analyse it's sys-/libcall bahavior? You will detect it.
> BTW, what's about adding a new pattern to your IDS's database?
> Thomas Biege, SuSE GmbH, Schanzaeckerstr. 10, 90443 Nuernberg
> Email: thomassuse.de Function: Security Support & Auditing
> "lynx -source http://www.suse.de/~thomas/thomas.pgp | pgp -fka"
> Key fingerprint = 09 48 F2 FD 81 F7 E7 98 6D C7 36 F1 96 6A 12 47
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