[Rule Tuning] Windows High-Severity Rules Revamp - 9

[w0rk3r]

Issues

Part of https://github.com/elastic/ia-trade-team/issues/619
Part of https://github.com/elastic/ia-trade-team/issues/844
Part of https://github.com/elastic/ia-trade-team/issues/205
Part of https://github.com/elastic/ia-trade-team/issues/636

Summary

This PR fixes/improves our Windows rules by:

• Improving our investigation guides to be question-driven and actionable, with clear pivots and specific information vs our old checklists
• Adding Investigate Timeline plugins to help analysts quickly pivot into related alerts, authentication events, file activity, child processes, network activity, directory-service changes, and follow-on Windows Security events
• Adding setup guides
• Adding Highlighted fields
• Fixing/Improving metadata where needed (Description, Mitre tags, references)
• Improving the order of the fields, so the most relevant information (Name, description, query) are visible without scrolling down too much
• Tunings where needed (Expand logic, exclude FPs, etc.)

Screenshots / Sample

Highlighted Fields:

Investigation Guides: Investigate Plugin

Clicking the investigation plugins launches Timeline with field values populated dynamically from alert fields.

[github-actions]

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.

[tradebot-elastic]

⛔️ Test failed

Results

• ❌ Script Execution via Microsoft HTML Application (eql)
  • coverage_issue: no_rta
  • stack_validation_failed: no_rta
• ❌ Suspicious Process Access via Direct System Call (eql)
  • coverage_issue: no_rta
  • stack_validation_failed: no_rta
• ❌ WDAC Policy File by an Unusual Process (eql)
  • coverage_issue: no_rta
  • stack_validation_failed: no_rta
• ❌ PowerShell Share Enumeration Script (kuery)
  • coverage_issue: no_rta
  • stack_validation_failed: no_rta
• ✅ Unusual File Creation - Alternate Data Stream (eql)
• ❌ Suspicious Managed Code Hosting Process (eql)
  • coverage_issue: no_rta
  • stack_validation_failed: no_rta
• ❌ Attempt to Install or Run Kali Linux via WSL (eql)
  • coverage_issue: no_rta
  • stack_validation_failed: no_rta
• ❌ Unusual Child Process from a System Virtual Process (eql)
  • coverage_issue: no_rta
  • stack_validation_failed: no_rta
• ✅ Unusual Executable File Creation by a System Critical Process (eql)
• ❌ Unusual Child Processes of RunDLL32 (eql)
  • coverage_issue: no_rta
  • stack_validation_failed: no_rta

[Mikaayenson]

Solid content updates (guides, setup, highlights, etc.). This is a departure in a positive way from most of the generated guides. Let's test this out and see how this impacts our users. Great work.

[tradebot-elastic]

⛔️ Test failed

Results

• ❌ Script Execution via Microsoft HTML Application (eql)
  • coverage_issue: no_rta
  • stack_validation_failed: no_rta
• ❌ Suspicious Process Access via Direct System Call (eql)
  • coverage_issue: no_rta
  • stack_validation_failed: no_rta
• ❌ WDAC Policy File by an Unusual Process (eql)
  • coverage_issue: no_rta
  • stack_validation_failed: no_rta
• ❌ PowerShell Share Enumeration Script (kuery)
  • coverage_issue: no_rta
  • stack_validation_failed: no_rta
• ✅ Unusual File Creation - Alternate Data Stream (eql)
• ❌ Suspicious Managed Code Hosting Process (eql)
  • coverage_issue: no_rta
  • stack_validation_failed: no_rta
• ❌ Attempt to Install or Run Kali Linux via WSL (eql)
  • coverage_issue: no_rta
  • stack_validation_failed: no_rta
• ❌ Unusual Child Process from a System Virtual Process (eql)
  • coverage_issue: no_rta
  • stack_validation_failed: no_rta
• ✅ Unusual Executable File Creation by a System Critical Process (eql)
• ❌ Unusual Child Processes of RunDLL32 (eql)
  • coverage_issue: no_rta
  • stack_validation_failed: no_rta