[Tuning] First Occurrence of STS GetFederationToken Request by User

[imays11]

Pull Request

Issue link(s):

• https://github.com/elastic/ia-trade-team/issues/616

Summary - What I changed

Rule is executing as expected, however it is alerting on failed requests. Low alert telemetry.

This tuning:

• removed markdown and edited description to be more specific
• reduced execution window for 1 min lookback
• name change to add AWS consistent with all other rules
• added references that reflect in the wild threats and persistence usage
• increased risk_score and severity to medium accounting for usage as persistence mechanism in the wild
• added Persistence tag and Mitre tactic, technique, subtechnique
• added event.outcome: success criteria to query
• edited investigation guide to be more accurate reflection of steps required for investigating alert, including appropriate response action
• added highlighted fields

Note: only IAMUser and Root user identities can call this actions so we can use aws.cloudtrail.user_identity.arn as the new terms field without worrying about Role vs Role + Session issue seen with other new_terms rules

How To Test

To test you can use this script which will create a new user, long term credentials, authenticate and run GetFederationToken API. To test manually, use an existing user identity with long term credentials and run the following or similar command (you must attach a policy):

aws sts get-federation-token --name UnauthorizedUser --policy-arns arn=arn:aws:iam::aws:policy/AdministratorAccess --duration-seconds 43200 

[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.
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Testing and Validation

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