On Fri, Jul 8, 2011 at 11:29 AM, dan (ddp) <[email protected]> wrote:
>
> if_sid: For this log message, is sid XXX a valid match>
> if_matched_sid: Has sid YYY matched a recent log message (but not
> necessarily this one)?
>

This is simplistic and partly wrong.

if_sid is basically correct. If sid XXX matches the current log
message, then use rule YYY instead:

<rule id="YYY" level="10">
  <if_sid>XXX</if_sid>
  <description>This rule should be triggered instead of XXX</description>
</rule>

if_matched_sid is generally used in frequency based rules, and
determines whether sid XXX has been triggered Z times in A seconds. :P

<rule id="YYY" frequency="3" timeframe="30" level="12">
  <if_matched_sid>XXX</if_matched_sid>
  <description>If XXX is triggered 5+ times in 30 seconds, YYY should
be triggered</description>
</rule>

HTH

Reply via email to