ArcSight Pro Tip #1 - type field

Welcome to the first of a 100 best practice posts, these range from newbie to advanced user and consist of tips, tricks and best practices for ArcSight.

Filter Criteria: type

When using the "event.type" CEF field in a filter or rule you have the following options:

Action, Base, Aggregated, Correlation

This is likely a field you want to leverage in ALL content!  Why? 

Well it specifies if you want to fire a correlation event from a base or non-correlation events, or subsequently if you would like your correlation event to be based on another correlation event!  You can have rules that trigger other rules and so on but be warned! 

Rules that do not specify:

type != Correlation 

Can easily end up in an infinite loop

Therefore this ArcSight Pro Tip is to begin all rule content specifically with this filter entry unless you specifically want to match on rule generated events (non-base events):

type != Correlation

Reminder != means "not equal to"


Happy hacking!


Greg

@threatstream

http://www.threatstream.com

Parents
  • This is a great general use tip. However, it's worth also adding that the console likes to put your "type != Correlation" condition at or near the very top of the conditions, which is good for resource types that query the database but really bad for rules. If it's the first condition in a rule and 90% of your events are non-correlation events, then 90% of your events match the first condition and have to move on to the second. (Instant entry in the "Partial Matches" list on the rules dashboard! )

    Always make sure this condition is near the bottom in a rule!

Reply
  • This is a great general use tip. However, it's worth also adding that the console likes to put your "type != Correlation" condition at or near the very top of the conditions, which is good for resource types that query the database but really bad for rules. If it's the first condition in a rule and 90% of your events are non-correlation events, then 90% of your events match the first condition and have to move on to the second. (Instant entry in the "Partial Matches" list on the rules dashboard! )

    Always make sure this condition is near the bottom in a rule!

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