Snort mailing list archives

Re: threshold.conf - event_filter dificulties.


From: James Lay <jlay () slave-tothe-box net>
Date: Fri, 10 Apr 2015 16:56:53 -0600

On Fri, 2015-04-10 at 08:54 -0400, Jean-Pierre Zurbrügg wrote:
Hello everyone,



Current setup:


Ubuntu 12.04.5 LTS  3.2.0-23-generic #36-Ubuntu SMP Tue Apr 10
20:39:51 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux
Snort Version 2.9.7.2 GRE (Build 177)
Using PCRE version: 8.12 2011-01-15
Using ZLIB version: 1.2.3.4
Compile options: 
./configure --enable-sourcefire
make
sudo make install


pulledpork was used to update rules, config:


rule_url=https://www.snort.org/reg-rules/|
snortrules-snapshot.tar.gz|<oink code>
rule_url=http://labs.snort.org/feeds/ip-filter.blf|IPBLACKLIST|open
rule_url=https://www.snort.org/reg-rules/|opensource.gz|<oink code>
rule_url=https://rules.emergingthreatspro.com/|emerging.rules.tar.gz|
open
ignore=deleted.rules,experimental.rules,local.rules
temp_path=/tmp
rule_path=/etc/snort/rules/snort.rules
local_rules=/etc/snort/rules/local.rules
sid_msg=/etc/snort/sid-msg.map
sid_msg_version=2
sid_changelog=/var/log/sid_changes.log
sorule_path=/usr/local/lib/snort_dynamicrules/
snort_path=/usr/local/bin/snort
config_path=/etc/snort/snort.conf
distro=Ubuntu-10-4
black_list=/etc/snort/rules/iplists/default.blacklist
IPRVersion=/etc/snort/rules/iplists
snort_control=/usr/local/bin/snort_control
 enablesid=/etc/snort/enablesid.conf
 dropsid=/etc/snort/dropsid.conf
 disablesid=/etc/snort/disablesid.conf
 modifysid=/etc/snort/modifysid.conf
version=0.7.0


We are trying to setup a global event_filter in hopes of controlling
the amount of duplicated events that get fired from the same src\dst
per second.
We see a bunch of alerts being fired multiple times whithin the same
timestamp.


Steps taken:
edit /etc/snort/threshold.conf:
-------add line: event_filter gen_id 0, sig_id 0, type limit, track
by_src, count 1, seconds 15
**** We have also tried track by dst and also tried individual
event_filter by rule gen\sig.
**** We have also tried using the deprecated 'threshold command'


edit /etc/snort/snort.conf
------ verify that we have this line added: include threshold.conf


Run snort with following command: snort -A console -q -u snort -g
snort -c /etc/snort/snort.conf -i eth0


Confirm we see the following lines in the output:


Apr 9 09:22:15 nth-garbage snort[398]:
+-----------------------[event-filter-global]----------------------------------
Apr 9 09:22:15 nth-garbage snort[398]: | gen-id=global sig-id=global
type=Limit     tracking=src count=1   seconds=15
Apr 9 09:22:15 nth-garbage snort[398]:
+-----------------------[event-filter-local]-----------------------------------
******************************* VERY LONG LIST OF EVENT-FILTER RULES
HERE **************************




We don't know what we are doing wrong. Events of the same rule get
fired multiple times within the same second. Examples:


gen 1 \ sig 2014473 --- ET INFO JAVA - Java Archive Download By
Vulnerable Client         
gen 1 \ sig 21646 ---EXPLOIT-KIT Blackhole exploit kit landing page
with specific structure[...]


Which event_filter takes priority, a Global or a local event filter? 


Any tips would be greatly appreciated!


Thanks in advance.

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Need to have the gen and sig match like so:

event_filter gen_id 1, sig_id 2014473, type limit, track by_src, count
1, seconds 15
event_filter gen_id 1, sig_id 21646, type limit, track by_src, count 1,
seconds 15

James
------------------------------------------------------------------------------
BPM Camp - Free Virtual Workshop May 6th at 10am PDT/1PM EDT
Develop your own process in accordance with the BPMN 2 standard
Learn Process modeling best practices with Bonita BPM through live exercises
http://www.bonitasoft.com/be-part-of-it/events/bpm-camp-virtual- event?utm_
source=Sourceforge_BPM_Camp_5_6_15&utm_medium=email&utm_campaign=VA_SF
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