Modsec2sguil is currently configured to send alerts to Sguil. ModSecurity can be configured to log any event or transaction, including 200 OK, 302 Redirect, etc. Modsec2sguil distinguishes between alerts and other events by only processing HTTP codes of 400 and higher. Since 0.8-dev2 there is a configuration directive to prevent certain codes, such as 404, from being treated as an alert.
Now I have the following idea. Since ModSecurity can log all events with details of request headers, response headers and POST message body, it may be interesting to just send all these events to Sguil. They should not be appearing as alerts, but having them in the database can perhaps be interesting. I know using flow data and full packet captures the same data can be accessed, but having it in the database makes querying it a lot easier and longer available.
Possible problems are mostly the performance hit the webserver may take for sending all these events to Sguil and the storage requirements in Sguil’s database. I estimate the events are about 1kb in size on average, so on a busy site this may cause the database to grow very rapidly. Of course this behavior would be optional so it can be disabled.
Any thoughts on this idea?