Snort mailing list archives
Re: Excluding a single IP from HOME_NET
From: Cees <celzinga () gmail com>
Date: Fri, 30 May 2008 14:11:38 +0200
Thanks all. ipvars seems to be exactly what I need! I've compiled Snort with SSL support, disabled some preprocessors and rules that stopped working, but it seems kinda buggy. Some examples: # Excluding an IP that ISN'T part of the original definition ipvar HOME_NET [10.0.0.0/8,![1.1.1.1]] ipvar EXTERNAL_NET !$HOME_NET Works # Excluding an IP that IS part of the original definition ipvar HOME_NET [10.0.0.0/8,![10.1.1.1]] ipvar EXTERNAL_NET !$HOME_NET ERROR: Undefined variable name: (./attack-responses.rules:26): EXTERNAL_NET # Excluding an ipvar ipvar PROXY [1.1.1.1] ipvar HOME_NET [10.0.0.0/8,![$PROXY]] ipvar EXTERNAL_NET !$HOME_NET Segmentation fault. Also interesing, the provided sample in README.variables is invalid ipvar HOME_NET [1.1.1.1,2.2.2.0/24,![2.2.2.2,2.2.2.3]] ipvar EXTERNAL_NET !$HOME_NET ERROR: Undefined variable name: (./attack-responses.rules:26): EXTERNAL_NET Can anyone confirm this? If I'm not the only one I'll report a bug Cees (BTW Jeff, a pass rule won't work since the IDS isn't placed inline.) On Thu, May 29, 2008 at 7:30 PM, Todd Wease <twease () sourcefire com> wrote:
Try var PROXY_SERVER 10.0.0.1 var HOME_NET [10.0.0.0/8,!$PROXY_SERVER<http://10.0.0.0/8,%21$PROXY_SERVER> ] var EXTERNAL_NET !$HOME_NET or try compiling with --enable-ipv6 and use 'ipvar' instead of 'var' Take a look at README.variables. Cees wrote:List, Is it possible to exclude a single IP from HOME_NET? Imagine a network that uses the 10.0.0.0/8 range, and HOME_NET and EXTERNAL_NET are defined as follows: var HOME_NET [10.0.0.0/8] var EXTERNAL_NET !$HOME_NET Now image all clients connect to the internet via a proxy server, eg 10.0.0.1. The problem arises that this setup won't detect any malware infections, since (allmost) all malware rules are written for client in HOME_NET accessing EXTERNAL_NET, eg: alert tcp $HOME_NET any -> $EXTERNAL_NET $HTTP_PORTS (msg:"ET MALWARE 180solutions Update Engine"; flow: to_server,established; content:"GET"; depth: 3; content:"Host|3a|"; within: 300; content:".1 80solutions.com"; within: 40; reference:url, www.safer-networking.org/index.php?page=threats&detail=212; classtype: trojan-activity; sid: 2000930; rev:7;) Is there any way to exclude the proxy server from HOME_NET? An ideal solution would be something like: var PROXY_SERVER = [10.0.0.1] var HOME_NET [10.0.0.0/8, !$PROXY_SERVER] var EXTERNAL_NET !$HOME_NET However, this syntax results in an error in the sfportscan preprocessor: ERROR: snort.conf(x) => Invalid ip_list to 'watch_ip' option (snort 2.8.1) Any ideas? Thanks, Cees ------------------------------------------------------------------------ ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ ------------------------------------------------------------------------ _______________________________________________ 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
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Current thread:
- Excluding a single IP from HOME_NET Cees (May 29)
- Re: Excluding a single IP from HOME_NET Jeff Kell (May 29)
- Re: Excluding a single IP from HOME_NET Todd Wease (May 29)
- Re: Excluding a single IP from HOME_NET Cees (May 30)
- Re: Excluding a single IP from HOME_NET Jack Pepper (May 30)
- Re: Excluding a single IP from HOME_NET Jeff Kell (May 30)
- Re: Excluding a single IP from HOME_NET Cees (May 30)
- Re: Excluding a single IP from HOME_NET Jack Pepper (May 30)
- Message not available
- Re: Excluding a single IP from HOME_NET Cees (Jun 06)
- Re: Excluding a single IP from HOME_NET Cees (May 30)