[New Rule] Azure AKS Ephemeral Container Added to Pod

[terrancedejesus]

Pull Request

Issue link(s):

• https://github.com/elastic/ia-trade-team/issues/725
• https://github.com/elastic/ia-trade-team/issues/875

Summary - What I changed

Detects an identity injecting an ephemeral (debug) container into a running AKS (Azure Kubernetes Service) pod via the pods/ephemeralcontainers subresource, excluding known AKS control-plane and platform identities. Ephemeral containers share the target pod's namespaces and give stealthy interactive access to its processes and mounted secrets without creating a new pod. Coverage includes workload service accounts (system:serviceaccount:*), so a compromised in-cluster token used to attach a debug container is not excluded.

How To Test

Query can be used in TRADE stack.

Checklist

• Added a label for the type of pr: bug, enhancement, schema, maintenance, Rule: New, Rule: Deprecation, Rule: Tuning, Hunt: New, or Hunt: Tuning so guidelines can be generated
• Added the meta:rapid-merge label if planning to merge within 24 hours
• Secret and sensitive material has been managed correctly
• Automated testing was updated or added to match the most common scenarios
• Documentation and comments were added for features that require explanation

Contributor checklist

• Have you signed the contributor license agreement?
• Have you followed the contributor guidelines?

[github-actions]

Rule: New - Guidelines

These guidelines serve as a reminder set of considerations when proposing a new rule.

Documentation and Context

• Detailed description of the rule.
• List any new fields required in ECS/data sources.
• Link related issues or PRs.
• Include references.

Rule Metadata Checks

• creation_date matches the date of creation PR initially 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, considering performance for diverse environments. Non ecs fields should be added to non-ecs-schema.json if not available in an integration.
• min_stack_comments and min_stack_version should be included if the rule is only compatible starting from a specific stack version.
• index pattern should be neither too specific nor too vague, ensuring it accurately matches the relevant data stream (e.g., use logs-endpoint.process-* for process data).
• integration should align with the index. If the integration is newly introduced, ensure the manifest, schemas, and new_rule.yaml template are updated.
• setup should include the necessary steps to configure the integration.
• note should include any additional information (e.g. Triage and analysis investigation guides, timeline templates).
• tags should be relevant to the threat and align/added to the EXPECTED_RULE_TAGS in the definitions.py file.
• threat, techniques, and subtechniques should map to ATT&CK always if possible.

New BBR Rules

• building_block_type should be included if the rule is a building block and the rule should be located in the rules_building_block folder.
• bypass_bbr_timing should be included if adding custom lookback timing to the rule.

Testing and Validation

• Provide evidence of testing and detecting the expected threat.
• Check for existence of coverage to prevent duplication.

[Copilot]

Pull request overview

This PR adds a new Azure AKS detection rule to identify non-system identities injecting ephemeral (debug) containers into running pods via the pods/ephemeralcontainers subresource, and updates the non-ECS schema to include additional AKS kube-audit fields referenced by the rule.

Changes:

• Added a new KQL/Kuery rule for AKS ephemeral container injection activity in azure.platformlogs kube-audit logs.
• Extended non-ecs-schema.json with additional azure.platformlogs.properties.log.* fields used by the rule and investigation fields.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 4 comments.

File	Description
rules/integrations/azure/execution_azure_aks_ephemeral_container_added.toml	New production rule + investigation guide for detecting AKS ephemeral container injection via kube-audit logs.
detection_rules/etc/non-ecs-schema.json	Adds schema entries for additional azure.platformlogs kube-audit fields needed by the new rule.