The TA mapped our bluecoat index as a Web cim compliant. Looking at our bluecoat index and reports we built on top and some of these fields, that we use are not defined at Web CIM
Therefore, is it possible to extend the cim definition with our own custom fields?
Sure, it is. You just need to create a new data model that is cloned from the CIM model. (you could just edit the existing - but best be safe during explorations).
1) Start by cloning the original model.
2) Add the field to a Dataset,
3) Search it.
At this point, you'll get a search of " | from datamodel:"Web_Extended.Web" and your new field should be in there. You'll want to change your correlation searches that make use of the Web.Web data model to use your new extended data model instead.
HTH, Good luck.
Thanks for the great Q&A! This topic is now added the CIM guide. However, cloning would create an entirely new model that wouldn't be referenced in any downstream searches. It would require extra diligence mentioned by memarshall63. So that part is not currently included in the instructions: