mitigations.md

Mitigation Strategies Analysis for stripe/stripe-python

Mitigation Strategy: Regular stripe-python Library Updates

1. Regular stripe-python Library Updates

• Mitigation Strategy: Regularly Update stripe-python Library
• Description:
  1. Establish a Schedule: Define a recurring schedule (e.g., monthly, quarterly) to check for updates to the stripe-python library.
  2. Monitor Release Notes: Subscribe to Stripe's developer changelog and the stripe-python library's release notes on GitHub to be informed about new versions and security patches.
  3. Test Updates in Non-Production: Before updating in production, update the library in a staging or development environment.
  4. Run Regression Tests: Execute thorough regression tests in the non-production environment to ensure the update doesn't introduce any breaking changes or regressions in your application's Stripe integration using stripe-python.
  5. Deploy to Production: After successful testing, update the stripe-python library in your production environment.
• Threats Mitigated:
  • Vulnerable Dependencies (High Severity): Outdated stripe-python library can contain known security vulnerabilities that attackers can exploit. Severity is high as it can lead to data breaches, application compromise, or denial of service specifically through vulnerabilities in the Stripe integration.
• Impact:
  • Vulnerable Dependencies: Significantly reduces risk. Applying updates patches known vulnerabilities in stripe-python, making exploitation much harder via the Stripe integration.
• Currently Implemented: Partially Implemented
  • We have a monthly security review, but checking stripe-python updates is not explicitly part of it.
• Missing Implementation:
  • Need to add a specific step in the monthly security review to check for stripe-python updates and include it in our dependency update process.
  • Automated dependency update checks are not yet in place for stripe-python.

Mitigation Strategy: Webhook Signature Verification using stripe-python

2. Webhook Signature Verification using stripe-python

• Mitigation Strategy: Implement Webhook Signature Verification using stripe-python
• Description:
  1. Retrieve Webhook Signing Secret: Obtain the webhook signing secret from your Stripe dashboard for each webhook endpoint you configure.
  2. Store Secret Securely: Store the webhook signing secret securely, similar to API keys (e.g., environment variables, secrets management).
  3. Verify Signature in Webhook Handler using stripe-python: In your application's webhook handler code:
     • Extract the Stripe-Signature header from the incoming webhook request.
     • Use stripe-python's webhook signature verification functionality (e.g., stripe.Webhook.construct_event) to verify the signature using the request payload, signature header, and your signing secret.
     • If signature verification fails, reject the webhook request and log the failure for security monitoring.
  4. Handle Valid Webhooks: Only process webhook events after successful signature verification using stripe-python.
• Threats Mitigated:
  • Webhook Forgery (High Severity): Without signature verification, attackers can send fake webhook requests to your application, potentially triggering malicious actions, data manipulation, or bypassing security controls within the Stripe integration logic.
• Impact:
  • Webhook Forgery: Eliminates the risk of processing forged webhooks. Ensures that only legitimate events originating from Stripe are processed by your application's Stripe webhook handler. stripe-python's built-in function makes this verification straightforward and reliable.
• Currently Implemented: Implemented
  • We have implemented webhook signature verification in our webhook handlers using stripe-python's stripe.Webhook.construct_event method.
• Missing Implementation:
  • No known missing implementation. We should regularly review webhook signature verification logic to ensure it remains correctly implemented and utilizes stripe-python's provided functions correctly.

Mitigation Strategy: Idempotency Keys with stripe-python

3. Idempotency Keys with stripe-python

• Mitigation Strategy: Utilize Idempotency Keys with stripe-python
• Description:
  1. Identify Critical API Requests: Determine which API requests made using stripe-python are critical and should be idempotent (e.g., charges, refunds, customer creation).
  2. Generate Idempotency Keys: Generate unique idempotency keys for each critical API request. This can be a UUID or any unique identifier generated on your application side.
  3. Pass Idempotency Keys in stripe-python Requests: When making critical API calls using stripe-python, include the generated idempotency key in the idempotency_key parameter of the API request.
  4. Handle API Errors and Retries: If API requests fail due to network issues or other transient errors, retry the request using the same idempotency key. stripe-python facilitates retries, and using the same key ensures idempotency.
• Threats Mitigated:
  • Accidental Duplicate Operations (Medium Severity): Network issues or application errors can lead to retries of API requests. Without idempotency, this can result in duplicate charges, refunds, or other unintended actions, leading to financial discrepancies or data inconsistencies within your Stripe integration.
• Impact:
  • Accidental Duplicate Operations: Eliminates the risk of duplicate operations caused by retries. Ensures that even if an API request is retried, the operation is performed only once by Stripe, preventing unintended side effects and maintaining data integrity in your Stripe interactions. stripe-python's support for passing idempotency keys makes this mitigation easy to implement.
• Currently Implemented: Partially Implemented
  • We use idempotency keys for some critical operations like charge creation, but not consistently across all relevant API calls made with stripe-python.
• Missing Implementation:
  • Need to review all critical API requests made using stripe-python and ensure idempotency keys are consistently implemented for all of them.
  • Develop a clear policy and guidelines for when to use idempotency keys in our Stripe integration.

These mitigation strategies are directly related to using the stripe-python library and are crucial for building a secure and reliable application that integrates with Stripe. Remember to continuously review and improve your security practices as your application and the threat landscape evolve.