phish phreek wrote:
> In the last rules file I emailed to the list, I choose IDs in the 12200
> range since the named rules were in the 12100 range. I've left the ipv4
> rules for 2k3 and 2k8 in the 12200 range and put the 2k8 ipv6 rules in
> the 12300 range.

This will be OK for testing, but you're probably better of using rule
IDs in the user range of 100,000-120,000 so that there aren't any
conflicts during an upgrade. When they get accepted into the project,
Daniel will assign a unique group of IDs.

> Before I send the updated decoders and rules, I wanted to get a better
> understanding of the rule alert levels and rule groups. I've been
> looking over some of the documentation between the manual and the FAQs.
> I'm not sure that either of them are documented? I've also not been able
> to find valid "log types" to monitor. In my case, I just used syslog and
> it's working but I'm not sure if I should use something else?

OSSEC Rule ID Groupings and Best Practices:
http://ossec.net/wiki/index.php/Know_How:RuleIDGrouping

As to the log type, are the DHCP logs in the event log format? In that
case, you may want to try <type>windows</type>.

> Where can I find out the alert level scale? Or, how should I assign
> alert levels to my rules? I've set all my rules to alert level 5 to start.

This should help: http://ossec.net/wiki/index.php/Know_How:Rules_Severity

In my experience, however, simply use this as a guide. If there is
something that warrants a larger or smaller severity then simply use
good judgment.

> Are the rule groups predefined or can I use my own? I've used some of
> the groups that I've seen defined in other rules such as
> "service_availability" but I've gone on to define my own such as
> "dhcp_lease_action","dhcp_maintenance","dhcp_dns_maintenance" and
> "dhcp_rogue_server".

You can make up your own groups, but try to use the pre-defined groups
where it makes sense. More info here:
http://ossec.net/wiki/index.php/Know_How:Rule_Groups

> Where is a list of valid log types that you define on the agent's
> ossec.conf file when you tell it to monitor a log?

You can use strftime or globbing in the log name definition, otherwise,
just feed it a log file and use the decoder as a guide for the log type.
One hint: single line ASCII log files can be defined as syslog even if
they aren't properly syslog-formatted.

One final tip: use the local_decoder.xml file until this is accepted
into the project, because if you don't, you might lose all your work
during an upgrade!

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