[New Rule] AWS IAM Credentials Added to a Bedrock API Key Phantom User

[bryans3c]

Pull Request

Issue link(s):

• https://github.com/elastic/ia-trade-team/issues/920

Summary - What I changed

Detects a standard IAM access key or console login profile being added to an Amazon Bedrock API key phantom user (BedrockAPIKey-*).

When a long-term Bedrock API key is created via the AWS Console, AWS silently provisions a BedrockAPIKey- IAM user with the AmazonBedrockLimitedAccess policy. That user exists only to back a bearer token and should never hold a standard access key or interactive login. Adding one converts a Bedrock-scoped identity into general-purpose IAM credentials that inherit the policy's broad Bedrock + IAM/VPC/KMS reconnaissance permissions and persist after the Bedrock key is revoked. There is no legitimate workflow that produces this, so it is near-zero false positive.

https://www.beyondtrust.com/blog/entry/aws-bedrock-security-api-keys
https://www.beyondtrust.com/blog/entry/aws-bedrock-security-guide-api-keys-detection-response

How To Test

Query can be used in TRADE stack and other telemetry stacks.

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.
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Testing and Validation

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

[Copilot]

Pull request overview

Adds a new Elastic detection rule to identify high-confidence privilege escalation/persistence behavior in AWS: adding standard IAM credentials (access keys or login profile) to Bedrock API key “phantom users” (BedrockAPIKey-*) created by the AWS Console.

Changes:

• Introduces a new ES|QL CloudTrail rule targeting CreateAccessKey, CreateLoginProfile, and UpdateLoginProfile against BedrockAPIKey-* users.
• Provides investigation guidance, false-positive rationale, and response recommendations tailored to the Bedrock phantom-user pivot.