Snort mailing list archives
Re: Question about !HOME_NET
From: "Nick Baronian" <kvetch () gmail com>
Date: Wed, 11 Oct 2006 12:33:26 -0400
Thanks Shirkdog, sorry ya my post wias clear. I had set EXTERNAL_NET to !$HOME_NET and I am getting logs for tons of internal addresses still. I see a ton like this. 00:04:48.084912 IP 10.20.16.10.3277 > 64.233.167.99.http: tcp 478 I have all other rules commented out right now so the only rule is alert tcp !$HOME_NET -> $EXTERNAL_NET any (msg:"NonCorp IP detected";) in other words alert tcp !$HOME_NET -> !$HOME_NET any (msg:"NonCorp IP detected";) I am not getting an alert log because I think my rule is right and nothing has triggered it but the snort.log file is logging everything. How can I get it to only log stuff in the rule and ignore the rest? I can't figure out if the -N flag is what I want because I haven't seen any nonCorp IP's in weeks so I haven't verified. I guess I will need to re-IP a box with a invalid IP to test. Regarding the policy about people jacking into the network, my address is 1600 Pennsylvania Avenue, DC ;). Yeah, we do have policies in place (plus you can't get into the building without an escort with you) the nonCorp IP's can't talk to anything but some of the older switches seem to be broadcasting their request and I want to find these switches using the link layer of the packet. We have something like 70odd locations and I need an easier way than reading the Firewall logs for catching vendors and whomever plugging into an open jack with non corp. IP's. I figure this way Snort can alert me and log the packet so I can make sure nothing too funny is going on. Thanks, Nick On 10/11/06, M. Shirk <shirkdog_list () hotmail com> wrote:
Well Snort can help detect such traffic, but you have a problem with your security policy and procedures if people are just showing up and jacking into the wall and having full access to the network (where is your addresss???? ) :-) Also, what is $EXTERNAL_NET set to? probably "any" in the snort.conf? And why are you using ALL of the private addresses? you should be using a variable that is something like var HOME_NET [10.111.0.0/16] var EVIL_NET !$HOME_NET More then likely, an on internal network, your sig will fire on every packet :-) Ok finchy, your turn. Shirkdog http://www.shirkdog.usFrom: "Nick Baronian" <kvetch () gmail com> To: "snort-users () lists sourceforge net" <snort-users () lists sourceforge net> Subject: [Snort-users] Question about !HOME_NET Date: Wed, 11 Oct 2006 10:47:00 -0400 I am trying to setup a simple rule but it doesn't appear to be working. We have has some issues with people plugging in their laptops to our corp. network. Some of these folks have static addresses and try to send some traffic outbound, while the traffic gets dropped at a firewall I want to log and alert on any non Home_NET IP's trying to go out. I thought it would be fairly easy just set home_net to something like var HOME_NET [172.0.0.0/8,10.0.0.0/8,192.168.0.0/16] and var HOME_NET [172.0.0.0/8,10.0.0.0/8,192.168.0.0/16] then comment out other rules in snort.conf except local.rule. In local rule set it to something like alert ip !HOME_NET any -> $EXTERNAL_NET any (msg:"nonwork routable IP detected";) I then start snort like snort -e -i eth1 -l /u01/snort -s -D & When I look at the log down /u01/snort it lists tons of IP's going from an IP like 10.30 or 172.x.x.x going to some random IP. How do I get my rules to only log the packets for non-Home_Net IP's trying to talk to other non-Home_Net IP's? Thanks, Nick ------------------------------------------------------------------------- Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 _______________________________________________ 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_________________________________________________________________ Be seen and heard with Windows Live Messenger and Microsoft LifeCams http://clk.atdmt.com/MSN/go/msnnkwme0020000001msn/direct/01/?href=http://www.microsoft.com/hardware/digitalcommunication/default.mspx?locale=en-us&source=hmtagline ------------------------------------------------------------------------- Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 _______________________________________________ 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
------------------------------------------------------------------------- Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 _______________________________________________ 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:
- Question about !HOME_NET Nick Baronian (Oct 11)
- Re: Question about !HOME_NET M. Shirk (Oct 11)
- Re: Question about !HOME_NET Joel Esler (Oct 11)
- Re: Question about !HOME_NET Nick Baronian (Oct 11)
- Re: Question about !HOME_NET Nick Baronian (Oct 11)
- Re: Question about !HOME_NET Todd Wease (Oct 11)
- Re: Question about !HOME_NET M. Shirk (Oct 11)