I am currently trying to filter EventCode 4703. I wanted to do this via blacklist but not fully block the EventCode but simply do like a regex to filter on Account Names ending in $ and drop those logs from sending to splunk. Also I am trying to filter 4688 and 4689. I was following this, https://gist.github.com/automine/a3915d5238e2967c8d44b0ebcfb66147 , guide but it doesn't seem to work for me.
[drop-eventcodes] REGEX = (?m)^EventCode=(4703|4688|4689) DEST_KEY = queue FORMAT = nullQueue
There is other solution where a regex expression is being used to filter out some specific events like EventCode 4624, so my suggestion is for checking how the data is after splunk indexed in order to get the correct regex expression to match the piece of the data you want to drop from indexing.