Creation or Modification of Domain Backup DPAPI private key

## Triage and analysis

Domain DPAPI Backup keys are stored on domain controllers and can be dumped remotely with tools such as Mimikatz. The resulting .pvk private key can be used to decrypt ANY domain user masterkeys, which then can be used to decrypt any secrets protected by those keys.

## Config

If enabling an EQL rule on a non-elastic-agent index (such as beats) for versions <8.2, events will not define `event.ingested` and default fallback for EQL rules was not added until 8.2, so you will need to add a custom pipeline to populate `event.ingested` to @timestamp for this rule to work.