Snort mailing list archives
Re: Alerts, Logs and DB's--Oh My!
From: Erek Adams <erek () theadamsfamily net>
Date: Wed, 13 Mar 2002 11:40:05 -0800 (PST)
On Wed, 13 Mar 2002 bthaler () webstream net wrote:
Geez! Now I'm really confused!
Great! You'll fit right in here! ;-)
Read this statement by Marty: "What this means in practical terms is that if the db plugin is in alert mode, it will only receive output from alert rules, whereas if it's in "log" mode it will receive output from both log and alert rules." This means that the database output plugin, configured to run in "log" mode will write both "alert" and "log" output to the database, right?
It means it will write "alert" and "log" _RULES_ to the DB. (More info below)
So if this is true, then why does the output plugin need to be set to "alert" to capture spp_portscan and evidently spp_anomsensor?
In spp_portscan.c you have this line: 1559: CallAlertFuncs(NULL, logMessage, NULL, &event); Now, when it gets sent back to snort, snort sees that info as an Alert, not a Log. As for Spade, well... I'm not much of a coder, but I'd be it's the same reason.
I may be missing something obvious here, but this doesn't make sense to me. If "log" logs both "alert" and "log" (does that make sense?), then we should see spp_portscan (and with it spp_anomsensor) with the output plugin set to "log" but we don't, so this must not be completely true. Please forgive my ignorance...
"Ignorance is cureable, stupidity is not."--My Calc teacher in college. :) Consider this: When plugins were first built into snort, there wasn't a lot of design in the framework. Now there is. IIRC, spp_portscan was the first pre-processor that was written. So you might see some wierd things going on in it.
On another note, I noticed that many of the fancier features of snort are dependant on the "alert" facility, which writes those pesky "alert" files to my HD, as well as those IP Address directories. I was under the impression that maximum performance/attack information would be achieved by having Snort output to a database on a remote host, as opposed to a local database or local logfiles. When I use the "alert" facility combined with the database output plugin, I still get the "alert", etc. files written locally. I understand that this is not a "bug" per se, but is just the way Snort works, but it seems counter-intuitive to me. I mean I'm going through all the trouble of maintaining a separate machine just to run MySQL and maximize performance, and Snort insists on writing files locally. This not only hinders performance, buy could be used as a way to DOS snort with "noise" filling my sensor's HD.
OK, consider using Barnyard and unified logging. At the present, it's still 'beta' but works fairly well from what I hear/see.
I need to run IDS on a 45Mb connection, so I need all the performance I can get. At the same time, I need as much information about incoming attacks as possible. I realize that this is a compromise, but it seems that Snort is "wasting" performance by writing these files, at least in my situation, since all of that info is already in the database.
Barnyard will become your friend. There are some folks here on the list who are doing a bit more than what you want. Just have a look back over the archives and grep for performance. You'll get more than you ever wanted to know. :)
Anyway, this is just my perspective...Let me know if I'm missing something here.
Ummm... Nope. Seem to be doin fine! :) ----- Erek Adams Nifty-Type-Guy TheAdamsFamily.Net _______________________________________________ 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:
- Spade ---What gives bthaler (Mar 12)
- Re: Spade ---What gives James Hoagland (Mar 12)
- Re: Spade ---What gives bthaler (Mar 13)
- Re: Spade ---What gives bthaler (Mar 13)
- Re: Spade ---What gives Erek Adams (Mar 13)
- Re: Spade ---What gives bthaler (Mar 13)
- Re: Spade ---What gives Erek Adams (Mar 13)
- Re: Spade ---What gives bthaler (Mar 13)
- Re: Spade ---What gives Erek Adams (Mar 13)
- Re: Spade ---What gives bthaler (Mar 13)
- Re: Alerts, Logs and DB's--Oh My! Erek Adams (Mar 13)
- Re: Spade ---What gives James Hoagland (Mar 12)