Snort mailing list archives
Re: Alert on web traffic instead of IP Address?
From: Jason Haar <Jason.Haar () trimble co nz>
Date: Thu, 13 Aug 2009 12:56:06 +1200
On 08/12/2009 02:40 AM, Joel Esler wrote:
Correct, it is *not* possible to put hostnames in a rule. It's probably better to write a rule on the content of the traffic than to try and track an IP.
More specifically, it would be *insane* for an IDS to do on-the-fly DNS lookups. Don't forget, if you have a rule that says "trigger an alert if someone connects to this.dns.host and then...", then the IDS would have to do DNS lookups for EVERY packet - just in case it matched. Also, the IDS only sees the IP, so it could only do PTR lookups - which may not match the A record (certainly true in your case of fast flux) Same principle applies to firewalls. Firewalls that support DNS only means they do the DNS lookup ONCE at boot-time, then they match on IP address thereafter. If you can get your IDS in front of your DNS servers you may have a shot. You could write rules to trigger when anyone did the actual DNS lookup of such hosts... -- Cheers Jason Haar Information Security Manager, Trimble Navigation Ltd. Phone: +64 3 9635 377 Fax: +64 3 9635 417 PGP Fingerprint: 7A2E 0407 C9A6 CAF6 2B9F 8422 C063 5EBB FE1D 66D1 ------------------------------------------------------------------------------ Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july _______________________________________________ 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:
- Alert on web traffic instead of IP Address? Isherwood, Jeffrey - AES (Aug 11)
- Re: Alert on web traffic instead of IP Address? Joel Esler (Aug 11)
- Re: Alert on web traffic instead of IP Address? Jason Haar (Aug 12)
- Re: Alert on web traffic instead of IP Address? Matt Olney (Aug 12)
- Re: Alert on web traffic instead of IP Address? CunningPike (Aug 13)
- Re: Alert on web traffic instead of IP Address? Jason Haar (Aug 12)
- Re: Alert on web traffic instead of IP Address? Joel Esler (Aug 11)
- Re: Alert on web traffic instead of IP Address? Frank Knobbe (Aug 14)