Windows Defender Disabled via Registry Modification

## Triage and analysis

Detections should be investigated to identify if the hosts and users are authorized to use this tool. As this rule detects post-exploitation process activity, investigations into this should be prioritized.

## 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.