Vulnerable code sample

import json

# This code is a conceptual representation of the vulnerability and not the
# actual source code from the SageMaker SDK. It simulates an API response
# structure that would have been returned by the AWS backend before the fix.

class MockSageMakerClient:
    """
    A mock client that simulates the behavior of the SageMaker API
    before the fix for CVE-2024-1777 (incorrectly referenced as CVE-2026-1777).
    """
    _training_jobs_db = {
        "my-vulnerable-training-job-01": {
            "TrainingJobName": "my-vulnerable-training-job-01",
            "TrainingJobArn": "arn:aws:sagemaker:us-east-1:123456789012:training-job/my-vulnerable-training-job-01",
            "TrainingJobStatus": "Completed",
            "ModelArtifacts": {
                "S3ModelArtifacts": "s3://my-sagemaker-bucket/output/model.tar.gz"
            },
            # THE VULNERABLE PART:
            # The API response includes sensitive key material in cleartext.
            # This key is intended for the ModelBuilder feature to sign model artifacts,
            # but it is being improperly exposed to any caller of DescribeTrainingJob.
            "ModelBuilder": {
                "Container": "123456789012.dkr.ecr.us-east-1.amazonaws.com/my-container:latest",
                "Schema": '{"input": [], "output": []}',
                "HMACSigningKey": "a_very_secret_hmac_key_that_should_not_be_exposed_abcdef123456"
            },
            "HyperParameters": {
                "learning_rate": "0.01",
                "epochs": "10"
            }
        }
    }

    def describe_training_job(self, TrainingJobName):
        """
        Simulates the vulnerable `describe_training_job` call, returning
        the full job description including the sensitive HMAC key.
        """
        job_details = self._training_jobs_db.get(TrainingJobName)
        if not job_details:
            raise ValueError("Training job not found")
        return job_details

if __name__ == "__main__":
    # 1. An actor (user, service, or potential attacker) has permissions to
    #    call 'describe_training_job'.
    sagemaker_client = MockSageMakerClient()
    training_job_name = "my-vulnerable-training-job-01"

    # 2. The actor calls the API to get details about the training job.
    print(f"Calling describe_training_job for: '{training_job_name}'...")
    response = sagemaker_client.describe_training_job(TrainingJobName=training_job_name)

    print("\n--- Full API Response (as received by the caller) ---")
    print(json.dumps(response, indent=2))
    print("------------------------------------------------------\n")

    # 3. The actor inspects the cleartext response and extracts the secret key.
    #    The SDK before the fix would have received this exact structure.
    try:
        exposed_key = response['ModelBuilder']['HMACSigningKey']
        print(f"[VULNERABILITY DEMONSTRATED]")
        print(f"The 'HMACSigningKey' was found in the cleartext response:")
        print(f"--> {exposed_key} <--")
        print("\nAn attacker with this key and S3 write permissions could now sign malicious artifacts.")
    except (KeyError, TypeError):
        print("HMACSigningKey not found in the response. The structure might be fixed.")