[FR] Upgrade eql to 1.0.1, align KQL with lark 1.x, and fix NTLM relay field comparison

[Mikaayenson]

Summary

• Fixes widespread rule execution failures.
• Root cause: [Rule Tuning] Potential Computer Account NTLM Relay Activity #6431 added length(host.name) == length(user.name) - 1, which SIEM EQL rejects (Comparisons against fields are not currently supported). local (pyeql) validation did not catch.
• Replaces that check with equivalent logic: mutual startswith~ for exact short-hostname match, or startswith~(host.name, concat(account, ".")) for FQDN — preserves the FP reduction intent without field arithmetic in ==.
• Pulls in logic from from eql upstream

[elastic-vault-github-plugin-prod]

⛔️ Test failed

Results

• ❌ Potential Computer Account NTLM Relay Activity (eql)
  • coverage_issue: no_rta
  • stack_validation_failed: no_rta

[Copilot]

Pull request overview

Fixes an Elasticsearch EQL execution failure in the Potential Computer Account NTLM Relay Activity rule by removing unsupported field-to-field arithmetic comparison and replacing it with equivalent hostname ↔ machine-account matching logic.

Changes:

• Updates the rule query to avoid length(host.name) == length(user.name) - 1 (unsupported field comparison) while preserving the intended “exact short-hostname or FQDN boundary” match behavior.
• Updates the rule updated_date to reflect the tuning date.

[elastic-vault-github-plugin-prod]

⛔️ Test failed

Results

• ❌ Potential Computer Account NTLM Relay Activity (eql)
  • coverage_issue: no_rta
  • stack_validation_failed: no_rta

[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.

[eric-forte-elastic]

Manual review, LGTM 👍

[elastic-vault-github-plugin-prod]

⛔️ Test failed

Results

• ❌ Potential Computer Account NTLM Relay Activity (eql)
  • coverage_issue: no_rta
  • stack_validation_failed: no_rta

[elastic-vault-github-plugin-prod]

⛔️ Test failed

Results

• ❌ Potential Computer Account NTLM Relay Activity (eql)
  • coverage_issue: no_rta
  • stack_validation_failed: no_rta

[elastic-vault-github-plugin-prod]

⛔️ Test failed

Results

• ❌ Potential Computer Account NTLM Relay Activity (eql)
  • coverage_issue: no_rta
  • stack_validation_failed: no_rta

[elastic-vault-github-plugin-prod]

⛔️ Test failed

Results

• ❌ Potential Computer Account NTLM Relay Activity (eql)
  • coverage_issue: no_rta
  • stack_validation_failed: no_rta

[elastic-vault-github-plugin-prod]

⛔️ Test failed

Results

• ❌ Potential Computer Account NTLM Relay Activity (eql)
  • coverage_issue: no_rta
  • stack_validation_failed: no_rta

[eric-forte-elastic]

We may want to change the file path here (maybe switch to a setup.py approach?) since I think it makes it incompatible with uv:

[eric-forte-elastic]

Logically I think this is good to go, just may want to update the way we are handling the dependency change for uv support.. Otherwise LGTM 👍