[Rule Tuning] 3rd Party EDR - Add Crowdstrike FDR support - 7

[w0rk3r]

Issues

Part of https://github.com/elastic/ia-trade-team/issues/242

Summary

Adjust simple (no sequence) rules to introduce support for Crowdstrike FDR. While full logic validation wasn't possible due to the lack of a test environment, the field population for each category was verified to ensure the data was correctly structured and populated as needed.

EDR field compatibility matrix may be of help to review, although the data provided by FDR is not consistent across event categories, and not even between event actions.

[protectionsmachine]

Rule: Tuning - Guidelines

These guidelines serve as a reminder set of considerations when tuning an existing rule.

Documentation and Context

• Detailed description of the suggested changes.
• Provide example JSON data or screenshots.
• Provide evidence of reducing benign events mistakenly identified as threats (False Positives).
• Provide evidence of enhancing detection of true threats that were previously missed (False Negatives).
• Provide evidence of optimizing resource consumption and execution time of detection rules (Performance).
• Provide evidence of specific environment factors influencing customized rule tuning (Contextual Tuning).
• Provide evidence of improvements made by modifying sensitivity by changing alert triggering thresholds (Threshold Adjustments).
• Provide evidence of refining rules to better detect deviations from typical behavior (Behavioral Tuning).
• Provide evidence of improvements of adjusting rules based on time-based patterns (Temporal Tuning).
• Provide reasoning of adjusting priority or severity levels of alerts (Severity Tuning).
• Provide evidence of improving quality integrity of our data used by detection rules (Data Quality).
• Ensure the tuning includes necessary updates to the release documentation and versioning.

Rule Metadata Checks

• updated_date matches the date of tuning PR merged.
• min_stack_version should support the widest stack versions.
• name and description should be descriptive and not include typos.
• query should be inclusive, not overly exclusive. Review to ensure the original intent of the rule is maintained.

Testing and Validation

• Validate that the tuned rule's performance is satisfactory and does not negatively impact the stack.
• Ensure that the tuned rule has a low false positive rate.

[Aegrah]

Wildcards are generally faster in process.command_line fields, due to process.args being an array.

[shashank-elastic]

+1 to Ruben suggestion on query optimisation