[New Rule] Adding Coverage for Unusual AWS S3 Object Encryption with SSE-C

[terrancedejesus]

Pull Request

Issue link(s):

• https://github.com/elastic/ia-trade-team/issues/529
• https://github.com/elastic/ia-trade-team/issues/272

Summary - What I changed

Adds detection coverage for ransom attempts by encrypting S3 objects with SSE-C via compromised AWS creds.

Identifies when AWS S3 objects stored in a bucket are encrypted using Server-Side Encryption with Customer-Provided Keys (SSE-C). Adversaries with compromised AWS credentials can encrypt objects in an S3 bucket using their own encryption keys, rendering the objects unreadable or recoverable without the key. This can be used as a form of ransomware to extort the bucket owner for the decryption key.

How To Test

• https://github.com/elastic/pwncloud/pull/17

Visit shared stack with the following query within the last 2 days.

event.dataset: "aws.cloudtrail"
    and event.provider: "s3.amazonaws.com"
    and event.action: "PutObject"
    and event.outcome: "success"
    and aws.cloudtrail.flattened.request_parameters.x-amz-server-side-encryption-customer-algorithm: "AES256"
    and aws.cloudtrail.flattened.additional_eventdata.SSEApplied: "SSE_C"

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]

Enhancement - Guidelines

These guidelines serve as a reminder set of considerations when addressing adding a new schema feature to the code.

Documentation and Context

• Describe the feature enhancement in detail (alternative solutions, description of the solution, etc.) if not already documented in an issue.
• Include additional context or screenshots.
• Ensure the enhancement includes necessary updates to the documentation and versioning.

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Testing

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Additional Schema Related Checks

• Ensure that the enhancement does not break existing functionality. (e.g., run make test-cli)
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• Exported detection rule(s) from Kibana to showcase the feature(s)
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• Updated necessary unit tests to accommodate the feature
• Applied min_compat restrictions to limit the feature to a specified minimum stack version
• Executed all unit tests locally with a test toml rule to confirm passing
• Included Kibana PR implementer as an optional reviewer for insights on the feature
• Implemented requisite downgrade functionality
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[Samirbous]

nice one! maybe add an additional one with threshold rule type (multi encryptions by same aws.cloudtrail.user_identity.arn)