Snort mailing list archives
Re: SYN flood detection
From: Erek Adams <erek () theadamsfamily net>
Date: Fri, 10 May 2002 14:32:56 -0700 (PDT)
On Fri, 10 May 2002, Pawel Rogocz wrote:
Thanks for bringing this up Erek.
Just thinking outloud.... :)
Now, I am not sure what the portscan processor really tries to do, if it only detects scans that are going to different ports. It will not detect scans going to the same port wheather they go to the same box or not.
Well, I can't agree with this statement. I've got listings in my portscan.log that clearly show this behavior. [...snip...] May 8 11:32:27 206.47.65.111:21 -> 10.10.10.77:21 SYN ******S* May 8 11:32:27 206.47.65.111:21 -> 10.10.10.83:21 SYN ******S* May 8 11:41:49 202.188.200.44:21 -> 10.10.10.66:21 SYN ******S* May 8 11:41:49 202.188.200.44:21 -> 10.10.10.68:21 SYN ******S* May 8 11:41:49 202.188.200.44:21 -> 10.10.10.69:21 SYN ******S* [...snip...] That's from two different scans, both across the same subnets. That scan only went to port 21 on each and every IP across my $HOME_NET.
The change to spp_portscan.c is trivial, but as Matt pointed out, you will have to think what your thresholds should be....
heh... Tuning, Retuning, and Tuning again. And who said running an IDS isn't like working on a car? ;-) ----- Erek Adams Nifty-Type-Guy TheAdamsFamily.Net _______________________________________________________________ Have big pipes? SourceForge.net is looking for download mirrors. We supply the hardware. You get the recognition. Email Us: bandwidth () sourceforge 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:
- SYN flood detection Pawel Rogocz (May 10)
- Re: SYN flood detection Matt Kettler (May 10)
- Re: SYN flood detection Erek Adams (May 10)
- Re: SYN flood detection Pawel Rogocz (May 10)
- Re: SYN flood detection Erek Adams (May 10)
- Re: SYN flood detection Erek Adams (May 10)
- Re: SYN flood detection Matt Kettler (May 10)