[New Rule] Kubernetes Pod Creation Using Common Debug or Base Images

[Aegrah]

Summary

Detects successful Kubernetes pod creation requests using commonly abused base and debugging container images such as BusyBox, Alpine, Ubuntu, Netshoot, and network multitool variants. These images are frequently used by attackers to deploy short-lived or interactive "throwaway" containers for reconnaissance, payload staging, or command execution due to their small footprint or built-in tooling.

[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.

[DefSecSentinel]

The image patterns have inconsistent coverage for private registries. *netshoot\:*, *network-multitool\:*, and *curl\:* use a leading wildcard to match images pulled from private registries (e.g., gcr.io/proj/netshoot:latest), but alpine*, busybox*, ubuntu\:*, and debian\:* don't. In hardened environments images are typically pulled from private registries, so gcr.io/myproject/alpine:3.18 would be missed. Would normalizing all patterns to use a leading wildcard (e.g., *alpine\:*, *busybox\:*) make sense here?

[DefSecSentinel]

T1610 (Deploy Container) is mapped to Execution in MITRE ATT&CK, not Defense Evasion. Should this second tactic block use a different technique, or be removed?

[terrancedejesus]

Its listed under both. Should be g2g

[terrancedejesus]

Thoughts on a BBR at first? Pod provisioning for these images I can imagine are quite common.

[imays11]

I agree, I think it's smart to make this a new terms though. But even then, these are all such commonly used container images that may not reduce noise enough. I would monitor as a BBR first in case noise is still an issue

[terrancedejesus]

Maybe make BBR first due to commonality of images used.