71 lines
3.0 KiB
Plaintext
71 lines
3.0 KiB
Plaintext
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include::../../../shared_content/secrets/description.adoc[]
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== Why is this an issue?
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As described in the
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https://learn.microsoft.com/en-us/azure/azure-functions/functions-bindings-http-webhook-trigger?tabs=python-v2%2Cisolated-process%2Cnodejs-v4%2Cfunctionsv2&pivots=programming-language-csharp#authorization-keys[Azure Functions documentation],
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Azure Functions let you use keys to make it harder to access your HTTP function endpoints *during development*.
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While keys provide a default security mechanism, distributing them in public
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apps is a bad practice and can lead to security and maintainability issues.
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=== What is the potential impact?
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The impact of this access depends on what the Azure Function does and what
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permissions the key has.
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There are three types of keys that can be used to authenticate requests to an
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Azure Function:
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* **Function key**: Provides access to a specific function.
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* **Host key**: Provides access to all functions within a function app.
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* **System key**: Provides access to all functions within a function app and allows for administrative actions.
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Leaking these keys can result in unintended access to the functions and data they control.
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Below are some real-world scenarios that illustrate some impacts of an attacker
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exploiting the key.
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:secret_type: authentication key
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include::../../../shared_content/secrets/impact/data_compromise.adoc[]
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include::../../../shared_content/secrets/impact/data_modification.adoc[]
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include::../../../shared_content/secrets/impact/financial_loss.adoc[]
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== How to fix it
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=== Use app-level security
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As described in the https://learn.microsoft.com/en-us/azure/azure-functions/functions-bindings-http-webhook-trigger?tabs=python-v2%2Cisolated-process%2Cnodejs-v4%2Cfunctionsv2&pivots=programming-language-csharp#secure-an-http-endpoint-in-production[Azure Functions documentation],
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you can secure your HTTP function endpoints by using app-level security, and
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remove the need to use hardcoded keys.
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The first step is thus to set the HTTP-triggered function authorization level to
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`anonymous`.
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Then, examples of app-level security include:
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* authentication/authorization, either from the framework of your choice or https://learn.microsoft.com/en-us/azure/app-service/overview-authentication-authorization#why-use-the-built-in-authentication[Built-in Azure App Service Authentication/Authorization]
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* Azure https://learn.microsoft.com/en-us/azure/api-management/api-management-policies#authentication-policies[API Management Authentication Policies]
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* request authentication with the https://learn.microsoft.com/en-us/azure/app-service/environment/integrate-with-application-gateway[Azure App Service Environment]
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=== Code examples
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==== Noncompliant code example
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[source,bash]
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----
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curl -G \
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'https://example.azurewebsites.net/api/example' \
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-d code=2PLqsO9INfpK8sgTS2BCsZXS6Dgzgz3bydKcq5TBcY8WAzFuqGlKRw==' # Noncompliant
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----
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== Resources
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include::../../../shared_content/secrets/resources/standards.adoc[]
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//=== Benchmarks
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