On Fri, Jan 6, 2012 at 10:49 PM, murf <[email protected]> wrote:
> Here I am again. I have a machine where the "big brother" stuff is

People still use big brother?

> being used to probe the
> sshd server. That generates, every 5 minutes, a message in /var/log/
> secure:
>
> Jan   6 21:20:01 sysname sshd[3567]: Bad protocol version
> identification 'quit' from UNKNOWN
>
> Which triggers the 5701 rule in the rules.
> 5701's match is:  "Bad Protocol version idendification"
>
> and it retaliates by trying to block the "UNKNOWN" ip in iptables....
> not cool.
>
> What I'd like to do is intro a new rule that is more specific to this
> situation,
>
> <match>Bad protocol version identification 'quit' from UNKNOWN</match>
>
> and only alarm if it's more frequent than 1 in 5 minutes.
>
> The existing 5701 should then kick in if there was no more specific
> match.
>
> How exactly (or even roughly) would this sort of thing be achieved?
>
> murf

What do you have so far?

Untested:
<rule id="STUFF" level="0">
  <if_sid>5701</if_sid>
  <match>Bad protocol version identification 'quit' from UNKNOWN$</match>
  <description>Ignore from bb</description>
</rule>

<rule id="STUFF1" level="7" frequency="0" timeframe="300">
  <if_sid>STUFF</if_sid>
  <description>More than 1 STUFF in 5 minutes</description>
</rule>

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