[Snort-users] HOME_NET, EXTERNAL_NET, var negatation and unwanted triggered rules

Denis Sacchet mailinglist at ...13903...
Wed Aug 16 11:21:22 EDT 2006


Hi everybody,

I try to setup a Snort installation onto my firewall, but in a standard
one, too much rules triggered, so I am trying to reduce unwanted
triggered rules to the minimum to only get the serious security problems.

To do that, I enable only one rules set (snmp.rules) because this rules
set triggered a lot of time because of my nagios/cacti monitoring
servers using snmp v2, and try to set up EXTERNAL_NET and HOME_NET to
avoid logging of SNMP message from local workstation to local workstation.

To do that, I set up as following :

var EXTERNAL_NET [!10.0.0.0/8]
var HOME_NET [10.0.0.0/8]

include $RULE_PATH/snmp.rules

and also :

var EXTERNAL_NET ![10.0.0.0/8]
var HOME_NET [10.0.0.0/8]

include $RULE_PATH/snmp.rules

and comment all the preprocessor and all the other rules files.

But I still got the following type of alert :

   	 ID  	 <
<https://saturne.kika.loc/base/base_qry_main.php?caller=&num_result_rows=5121&current_view=0&sort_order=sig_a> Signature >
<https://saturne.kika.loc/base/base_qry_main.php?caller=&num_result_rows=5121&current_view=0&sort_order=sig_d> 
	 <
<https://saturne.kika.loc/base/base_qry_main.php?caller=&num_result_rows=5121&current_view=0&sort_order=time_a> Timestamp >
<https://saturne.kika.loc/base/base_qry_main.php?caller=&num_result_rows=5121&current_view=0&sort_order=time_d> 
	 <
<https://saturne.kika.loc/base/base_qry_main.php?caller=&num_result_rows=5121&current_view=0&sort_order=sip_a> Source Address >
<https://saturne.kika.loc/base/base_qry_main.php?caller=&num_result_rows=5121&current_view=0&sort_order=sip_d> 
	 <
<https://saturne.kika.loc/base/base_qry_main.php?caller=&num_result_rows=5121&current_view=0&sort_order=dip_a> Dest. Address >
<https://saturne.kika.loc/base/base_qry_main.php?caller=&num_result_rows=5121&current_view=0&sort_order=dip_d> 
	 <
<https://saturne.kika.loc/base/base_qry_main.php?caller=&num_result_rows=5121&current_view=0&sort_order=proto_a> Layer 4 Proto >
<https://saturne.kika.loc/base/base_qry_main.php?caller=&num_result_rows=5121&current_view=0&sort_order=proto_d> 

	#0-(1-3835)
<https://saturne.kika.loc/base/base_qry_alert.php?submit=%230-%281-3835%29&sort_order=>
	[cve <http://cve.mitre.org/cgi-bin/cvename.cgi?name=2002-0013>] [icat
<http://icat.nist.gov/icat.cfm?cvename=CAN-2002-0013>] [cve
<http://cve.mitre.org/cgi-bin/cvename.cgi?name=2002-0012>] [icat
<http://icat.nist.gov/icat.cfm?cvename=CAN-2002-0012>] [bugtraq
<http://www.securityfocus.com/bid/4132>] [bugtraq
<http://www.securityfocus.com/bid/4089>] [bugtraq
<http://www.securityfocus.com/bid/4088>] [local
<https://saturne.kika.loc/base/signatures/1417.txt>] [snort
<http://www.snort.org/pub-bin/sigs.cgi?sid=1417>] SNMP request udp
2006-08-16 16:35:03 	10.70.30.4
<https://saturne.kika.loc/base/base_stat_ipaddr.php?ip=10.70.30.4&netmask=32>:35464
	10.40.0.2
<https://saturne.kika.loc/base/base_stat_ipaddr.php?ip=10.40.0.2&netmask32>:161
	UDP
	#1-(1-3836)
<https://saturne.kika.loc/base/base_qry_alert.php?submit=%231-%281-3836%29&sort_order=>
	[cve <http://cve.mitre.org/cgi-bin/cvename.cgi?name=2002-0013>] [icat
<http://icat.nist.gov/icat.cfm?cvename=CAN-2002-0013>] [cve
<http://cve.mitre.org/cgi-bin/cvename.cgi?name=2002-0012>] [icat
<http://icat.nist.gov/icat.cfm?cvename=CAN-2002-0012>] [bugtraq
<http://www.securityfocus.com/bid/4132>] [bugtraq
<http://www.securityfocus.com/bid/4089>] [bugtraq
<http://www.securityfocus.com/bid/4088>] [local
<https://saturne.kika.loc/base/signatures/1417.txt>] [snort
<http://www.snort.org/pub-bin/sigs.cgi?sid=1417>] SNMP request udp
2006-08-16 16:35:03 	10.70.30.4
<https://saturne.kika.loc/base/base_stat_ipaddr.php?ip=10.70.30.4&netmask=32>:35464
	10.40.0.2
<https://saturne.kika.loc/base/base_stat_ipaddr.php?ip=10.40.0.2&netmask32>:161
	UDP
	#2-(1-3837)
<https://saturne.kika.loc/base/base_qry_alert.php?submit=%232-%281-3837%29&sort_order=>
	[cve <http://cve.mitre.org/cgi-bin/cvename.cgi?name=2002-0013>] [icat
<http://icat.nist.gov/icat.cfm?cvename=CAN-2002-0013>] [cve
<http://cve.mitre.org/cgi-bin/cvename.cgi?name=2002-0012>] [icat
<http://icat.nist.gov/icat.cfm?cvename=CAN-2002-0012>] [bugtraq
<http://www.securityfocus.com/bid/4132>] [bugtraq
<http://www.securityfocus.com/bid/4089>] [bugtraq
<http://www.securityfocus.com/bid/4088>] [local
<https://saturne.kika.loc/base/signatures/1417.txt>] [snort
<http://www.snort.org/pub-bin/sigs.cgi?sid=1417>] SNMP request udp
2006-08-16 16:35:03 	10.70.30.4
<https://saturne.kika.loc/base/base_stat_ipaddr.php?ip=10.70.30.4&netmask=32>:35464
	10.70.20.2
<https://saturne.kika.loc/base/base_stat_ipaddr.php?ip=10.70.20.2&netmask32>:161
	UDP
	#3-(1-3838)
<https://saturne.kika.loc/base/base_qry_alert.php?submit=%233-%281-3838%29&sort_order=>
	[cve <http://cve.mitre.org/cgi-bin/cvename.cgi?name=2002-0013>] [icat
<http://icat.nist.gov/icat.cfm?cvename=CAN-2002-0013>] [cve
<http://cve.mitre.org/cgi-bin/cvename.cgi?name=2002-0012>] [icat
<http://icat.nist.gov/icat.cfm?cvename=CAN-2002-0012>] [bugtraq
<http://www.securityfocus.com/bid/4132>] [bugtraq
<http://www.securityfocus.com/bid/4089>] [bugtraq
<http://www.securityfocus.com/bid/4088>] [local
<https://saturne.kika.loc/base/signatures/1417.txt>] [snort
<http://www.snort.org/pub-bin/sigs.cgi?sid=1417>] SNMP request udp
2006-08-16 16:35:04 	10.70.30.4
<https://saturne.kika.loc/base/base_stat_ipaddr.php?ip=10.70.30.4&netmask=32>:35464
	10.70.20.2
<https://saturne.kika.loc/base/base_stat_ipaddr.php?ip=10.70.20.2&netmask32>:161
	UDP


in my BASE frontend.

Could someone help to figure out how to configure my NET variable to
avoid such alert to be logged.

Thanks in advance

Best regards

Denis Sacchet




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