Patched code sample

import ssl
import requests
from requests.adapters import HTTPAdapter
from urllib3.poolmanager import PoolManager

# This code represents how a fix for a TLS hostname verification vulnerability,
# such as the one described in CVE-2026-15925, would be implemented.
# The vulnerability stems from not checking if the server's certificate
# hostname matches the hostname the client is connecting to.
# The fix is to ensure hostname checking is explicitly enabled.

class SnowflakeSecureHttpAdapter(HTTPAdapter):
    """
    A custom requests HTTP Adapter that enforces secure TLS settings,
    specifically ensuring hostname verification is enabled.
    """
    def init_poolmanager(self, connections, maxsize, block=False, **pool_kwargs):
        """
        Creates a PoolManager that enforces secure TLS settings.
        """
        # The core of the fix is creating a proper SSL/TLS context.
        # ssl.create_default_context() provides a secure baseline for client sockets.
        # By default, it sets:
        # 1. `verify_mode` to `ssl.CERT_REQUIRED`.
        # 2. `check_hostname` to `True`.
        #
        # The vulnerable code would have likely used a context where
        # `check_hostname` was set to `False`, or used an older, less secure
        # method of context creation that did not enable it by default.
        ssl_context = ssl.create_default_context()
        
        # This explicit re-affirmation is for clarity and defense-in-depth,
        # ensuring the critical security feature is active. This directly
        # mitigates the risk of a Man-in-the-Middle (MITM) attack where
        # an attacker presents a valid certificate for a different domain.
        ssl_context.check_hostname = True
        ssl_context.verify_mode = ssl.CERT_REQUIRED

        # Attach the secure context to the pool manager.
        self.poolmanager = PoolManager(
            num_pools=connections,
            maxsize=maxsize,
            block=block,
            ssl_context=ssl_context,
            **pool_kwargs
        )

# --- Example Usage (demonstrating how the fixed connector would use it) ---

# In the fixed Snowflake Connector (e.g., version 4.7.1 or later), the
# internal HTTP session would be configured to use this secure adapter.

def create_fixed_snowflake_session(snowflake_host):
    """
    Creates a requests.Session object configured with the secure adapter.
    This simulates the corrected behavior in the Snowflake Connector.
    """
    session = requests.Session()
    secure_adapter = SnowflakeSecureHttpAdapter()
    
    # Mount the secure adapter for all HTTPS connections.
    session.mount(f"https://{snowflake_host}", secure_adapter)
    
    return session

if __name__ == '__main__':
    # This example demonstrates making a request with the fixed configuration.
    # An attacker attempting a MITM attack against this client would fail
    # because the client would reject the attacker's certificate if its
    # hostname did not match 'my-account.snowflakecomputing.com'.
    
    SNOWFLAKE_ACCOUNT_HOST = "my-account.snowflakecomputing.com"
    
    # Create a session that enforces hostname verification.
    secure_session = create_fixed_snowflake_session(SNOWFLAKE_ACCOUNT_HOST)
    
    login_url = f"https://{SNOWFLAKE_ACCOUNT_HOST}/session/v1/login-request"
    
    print(f"Attempting to connect to {login_url} with secure TLS settings...")
    
    try:
        # This request will now correctly validate the certificate AND hostname.
        # NOTE: This is a conceptual example; a real login requires a POST with data.
        response = secure_session.get(login_url, timeout=5)
        print("Connection successful (or received expected server response).")
        print(f"Status Code: {response.status_code}")
    except requests.exceptions.SSLError as e:
        # This is the error that would occur during a MITM attack with a
        # mismatched hostname, proving the fix is working.
        print(f"SSL Error occurred, as expected during a MITM attack: {e}")
    except requests.exceptions.RequestException as e:
        print(f"A network error occurred: {e}")