[New Rule] Instance Metadata Service (IMDS) API Requests - Linux

[terrancedejesus]

Pull Request

Issue link(s): https://github.com/elastic/ia-trade-team/issues/272

Summary - What I changed

Adding a new detection rule for unusual instance metadata service (IMDS) API requests. The IMDS has a global API for cloud service providers that will allow compute instance information retrieval, as well as can facilitate federated authentication and credential access. Adversaries, with compromised credentials or instance, may leverage a custom binary or native tools to send requests to IMDS' API for instance information or event temporary credential requests.

How To Test

Personal stack

Telemetry

Last 4 months there is ~36 alerts that match this. A majority of these are FP for a specific custom shellscript by a client that should be an exception rather than global exclusion in the query.

Checklist

• [x] Added a label for the type of pr: bug, enhancement, schema, 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
• [x] 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?

[protectionsmachine]

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.

[terrancedejesus]

Added event.type and event.action to the sequence, as the screenshot you provided detects a UID change event followed by a network event, rather than a process execution event. You might want to go back and check whether the query still works as intended with this change.

joining on process.entity_id and process.parent.entity_id for the sequences does not match the expected events, hence the image you pointed out. Rather, they entity IDs for both parent and child process are the same so I added process.parent.entity_id to the initial sequence by ... instead.