Re: Alert classification and priority

[Gary_Portnoy () itginc com]

>   priority: <value>;
> You can add it to each rule to set the priority. If no priority is
> set (as with nearly all default rules) the priority is taken via
> the classtype key which relates to the classification.config file.

I was looking for something more in the way of threshold.conf where I 
could change the priorities without changing the rule files, so that 
upgrading to new rules doesn't reset them back to default priority values. 
 The way I see it, the rule files should not be changed, any local 
customizations should be done via instance-specific files, like 
snort.conf, threshold.conf, local.rules, etc. 

> Even barnyard does not check for a changed priority of a rule and 
> will still use the old prioity.

As far as I understand, unified plugin just writes out the event with all 
the relevant info and barnyard looks at classification.config and 
determines the priority.  So one way to achieve what I am trying to do 
with barnyard (i am focusing on it because that's what I am using) would 
be to create a different classification type with a different priority and 
then use that classification type in my rules.  Barnyard then should 
(should being the keyword, i haven't tried this) log the correct 
classtype/priority to the database.  But again, this requires me to change 
the rules files.  What I want is a priority.config file where I can 
override the default priority by saying something along the lines of:

gen_id 1, sig_id 555, priority 3

I guess I can add this to the wish list. :)

-g-
-------------------------------------------
Gary Portnoy
Information Security Analyst
ITG, Inc.




Dirk Geschke <Dirk_Geschke () genua de>
06/03/2004 03:20 AM

 
        To:     Gary_Portnoy () itginc com
        cc:     snort-users () lists sourceforge net, Dirk_Geschke () genua de
        Subject:        Re: [Snort-users] Alert classification and priority


Hi Gary,

> Is there any way to de-couple alert classification from priority on a 
> rule-by-rule basis in a local type file?

yes of course: snort/docs/snort_manual.pdf, chapter 2.4.6 Priority

   priority: <value>;

You can add it to each rule to set the priority. If no priority is
set (as with nearly all default rules) the priority is taken via
the classtype key which relates to the classification.config file.

But be aware, if you use the database output plugin then the it
may still show the old priority since this value is not checked.

Of course, you can use FLoP (http://www.geschke-online.de/FLoP)
with the DBTrust option enabled. This will take care of the
changed priority. (Even barnyard does not check for a changed
priority of a rule and will still use the old prioity.)

BTW: With FLoP-1.2.3 there is a perl script called rules.pl
which will insert all signatures with references to the database.
This script is also able to add signatures with a range of priorities
set. (I think it is not uncommon to have different priorities for
the same rule depending on the place where snort sniffs.)

Best regards

Dirk






-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
This message is for the named person's use only. This communication is for 
informational purposes only and has been obtained from sources believed to 
be reliable, but it is not necessarily complete and its accuracy cannot be 
guaranteed. It is not intended as an offer or solicitation for the purchase
or sale of any financial instrument or as an official confirmation of any
transaction. Moreover, this material should not be construed to contain any
recommendation regarding, or opinion concerning, any security. It may
contain confidential, proprietary or legally privileged information. No
confidentiality or privilege is waived or lost by any mistransmission. If
you receive this message in error, please immediately delete it and all
copies of it from your system, destroy any hard copies of it and notify the
sender. You must not, directly or indirectly, use, disclose, distribute, 
print, or copy any part of this message if you are not the intended 
recipient.  Any views expressed in this message are those of the individual
sender, except where the message states otherwise and the sender is 
authorized to state them to be the views of any such entity.

ITG Inc. reserves the right to monitor and archive all electronic 
communications through its network. 

ITG Inc. Member NASD, SIPC
-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-



-------------------------------------------------------
This SF.Net email is sponsored by the new InstallShield X.
> From Windows to Linux, servers to mobile, InstallShield X is the one
installation-authoring solution that does it all. Learn more and
evaluate today! http://www.installshield.com/Dev2Dev/0504
_______________________________________________
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