Skip to content

Conversation

w0rk3r
Copy link
Contributor

@w0rk3r w0rk3r commented Jun 10, 2025

Summary

Adjust Powershell rules logic, exclude noisy patterns and bump severity (on non-noisy rules).

@w0rk3r w0rk3r self-assigned this Jun 10, 2025
@w0rk3r w0rk3r added Rule: Tuning tweaking or tuning an existing rule OS: Windows windows related rules Domain: Endpoint backport: auto labels Jun 10, 2025
Copy link
Contributor

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
Copy link

tradebot-elastic commented Jun 10, 2025

⛔️ Test failed

Results
  • ❌ Potential PowerShell Obfuscation via Invalid Escape Sequences (esql)
    • coverage_issue: no_rta
    • stack_validation_failed: no_rta
  • ❌ Potential PowerShell Obfuscation via Special Character Overuse (esql)
    • coverage_issue: no_rta
    • stack_validation_failed: no_rta
  • ❌ Potential PowerShell Obfuscation via String Reordering (esql)
    • coverage_issue: no_rta
    • stack_validation_failed: no_rta
  • ❌ Potential PowerShell Obfuscation via String Concatenation (esql)
    • coverage_issue: no_rta
    • stack_validation_failed: no_rta
  • ❌ Potential PowerShell Obfuscation via High Numeric Character Proportion (esql)
    • coverage_issue: no_rta
    • stack_validation_failed: no_rta

@tradebot-elastic
Copy link

tradebot-elastic commented Jun 17, 2025

⛔️ Test failed

Results
  • ❌ Potential PowerShell Obfuscation via Invalid Escape Sequences (esql)
    • coverage_issue: no_rta
    • stack_validation_failed: no_rta
  • ❌ Potential PowerShell Obfuscation via Special Character Overuse (esql)
    • coverage_issue: no_rta
    • stack_validation_failed: no_rta
  • ❌ Potential PowerShell Obfuscation via String Reordering (esql)
    • coverage_issue: no_rta
    • stack_validation_failed: no_rta
  • ❌ Potential PowerShell Obfuscation via String Concatenation (esql)
    • coverage_issue: no_rta
    • stack_validation_failed: no_rta
  • ❌ Potential PowerShell Obfuscation via High Numeric Character Proportion (esql)
    • coverage_issue: no_rta
    • stack_validation_failed: no_rta

@tradebot-elastic
Copy link

tradebot-elastic commented Jun 17, 2025

⛔️ Test failed

Results
  • ❌ Potential PowerShell Obfuscation via Invalid Escape Sequences (esql)
    • coverage_issue: no_rta
    • stack_validation_failed: no_rta
  • ❌ Potential PowerShell Obfuscation via Special Character Overuse (esql)
    • coverage_issue: no_rta
    • stack_validation_failed: no_rta
  • ❌ Potential PowerShell Obfuscation via String Reordering (esql)
    • coverage_issue: no_rta
    • stack_validation_failed: no_rta
  • ❌ Potential PowerShell Obfuscation via String Concatenation (esql)
    • coverage_issue: no_rta
    • stack_validation_failed: no_rta
  • ❌ Potential PowerShell Obfuscation via High Numeric Character Proportion (esql)
    • coverage_issue: no_rta
    • stack_validation_failed: no_rta

@tradebot-elastic
Copy link

tradebot-elastic commented Jun 17, 2025

⛔️ Test failed

Results
  • ❌ Potential PowerShell Obfuscation via Invalid Escape Sequences (esql)
    • coverage_issue: no_rta
    • stack_validation_failed: no_rta
  • ❌ Potential PowerShell Obfuscation via Special Character Overuse (esql)
    • coverage_issue: no_rta
    • stack_validation_failed: no_rta
  • ❌ Potential PowerShell Obfuscation via String Reordering (esql)
    • coverage_issue: no_rta
    • stack_validation_failed: no_rta
  • ❌ Potential PowerShell Obfuscation via String Concatenation (esql)
    • coverage_issue: no_rta
    • stack_validation_failed: no_rta
  • ❌ Potential PowerShell Obfuscation via High Numeric Character Proportion (esql)
    • coverage_issue: no_rta
    • stack_validation_failed: no_rta

@w0rk3r w0rk3r merged commit 3bc5708 into main Jun 17, 2025
12 checks passed
@w0rk3r w0rk3r deleted the posh_esql_tuning branch June 17, 2025 13:36
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Labels
backport: auto Domain: Endpoint OS: Windows windows related rules Rule: Tuning tweaking or tuning an existing rule
Projects
None yet
Development

Successfully merging this pull request may close these issues.

4 participants