Snort mailing list archives
Re: false positive generator
From: Dirk Geschke <Dirk_Geschke () genua de>
Date: Wed, 11 Feb 2004 13:06:52 +0100
Hi Bob,
Perhaps I am missing something, but why do you want to generate false positives exactly? Unless you are attempting to demonstrate how a sensor handles (or does not handle) false positives (i.e. in this case, I think you are really talking about stateless attacks, ones where the 3-way handshake has not occurred and only payload is being sent) then tools like Stick/Sneeze/Snot are not much use to you. You can check out our IDS/IPS reports at www.nss.co.uk/ids if you want to see how sensors handle stateless attacks and other types of false positives.
maybe someone will do his own tests on stateless attacks? There is of course one valid point to test a sensor. If you see how it works with stateless attacks you can verify how the sensor works with a high attack rate. Think of the behaviour of the output plugins, do they work well on high load? Does snort start to drop packages on this scenario? Yes, of course, you don't get a result for real attacks where the 3-way-handshake must be successfully applied.
Try using real attack traffic replayed using TCPREPLAY, or a tool like Blade IDS Informer/Firewall Informer which does the same thing but all wrapped up in a nice GUI and with plenty of pre-defined attacks included. That way, you will see some "real" attacks appearing in your database.
Yeah, but if you don't have such tools/packets for this tests and you want to create a very high attack rate to see if the database is able to handle it? How about stateless UDP attacks? They are still possible. So if you are able to generate a high load of UDP alerts then it would be likely that snort won't recognize the real TCP attack due to dropping some packets so that he won't see the established connection. I think these are all valid points which would justify to work with such false positive generator.
Be aware that not ALL the test cases included with the Blade software are good - we tend to use real exploit traffic or test cases we have generated in house to ensure complete control, but IDS/Firewall Informer make the replay easy.
Not everyone has this kind of environment for tests... For my environment I was simply testing if FLoP is able to work with a very high rate on alerts which should all be saved in a database. So every database has limitations on the INSERT rate which is usually much slower than the possible alert generating of snort. Think of a databas able to insert about 200 alerts per second and an alert rate of 2000 packets per second. Is it possible to store all alerts in the database? Or are some lost? Or does snort drop packets due to a slow output plugin? All these questions can be answered with some tools like the "fpg" program. And that was the idea why I wrote it. I think you may now see why this kind of alert generators may be useful... Best regards Dirk ------------------------------------------------------- The SF.Net email is sponsored by EclipseCon 2004 Premiere Conference on Open Tools Development and Integration See the breadth of Eclipse activity. February 3-5 in Anaheim, CA. http://www.eclipsecon.org/osdn _______________________________________________ Snort-users mailing list Snort-users () lists sourceforge net Go to this URL to change user options or unsubscribe: https://lists.sourceforge.net/lists/listinfo/snort-users Snort-users list archive: http://www.geocrawler.com/redir-sf.php3?list=snort-users
Current thread:
- RE: false positive generator Bob Walder (Feb 11)
- Re: false positive generator Dirk Geschke (Feb 11)
- <Possible follow-ups>
- RE: false positive generator Bob Walder (Feb 11)
- Re: false positive generator Dirk Geschke (Feb 11)