Can someone pls teach me the way to write a regex for searching ELM logs under ELM > Data?
1. AND (if I want to find logs where both string "4624" and a particular source IP that occurred in a single log)?
2. OR (if I want to find logs on a device where "4624" or "4634" have occured and pull out the logs those contain those strings?)
I'd run get Packet/ELM Archive on a few events of a similar type from your normalised ESM events, and stick them into a site like RegExr: Learn, Build, & Test RegEx and play around with building some regex. I'm no expert in regex myself, but have usually used that to work out how to do what I've needed, whether it was efficient is a different matter of course.
Ideally you also want to identify something more that's common about the particular event type of the log ( and Shift+select only the devices you need when on the ELM Search screen). If you're not expecting too many events, '46(2|3)4' might work for the second, and simply '4624.+127.0.0.1' for the first.