Skip to content

Wallarm Free API Firewall

Light-weighted Wallarm API Firewall protects your API endpoints in cloud-native environments with API schema validation. Wallarm API Firewall relies on a positive security model allowing calls that match a predefined API specification, while rejecting everything else.

The product is completely free, available at DockerHub and already got 10M pulls.

Please star repository to support this project https://hub.docker.com/r/wallarm/api-firewall

API schema validation and positive security model

When starting API Firewall, you should provide the OpenAPI 3.0 specification of the application to be protected with API Firewall. The started API Firewall will operate as a reverse proxy and validate whether requests and responses match the schema defined in the specification.

The traffic that does not match the schema will be logged using the STDOUT and STDERR Docker services or blocked (depending on the configured API Firewall operation mode). If operating in the logging mode and detecting the traffic on endpoints that are not included in the specification, API Firewall also logs these endpoints as the shadow ones (except for endpoints returning the code 404).

API Firewall scheme

Provided API schema should be described using the OpenAPI 3.0 specification in the YAML or JSON file (.yaml, .yml, .json file extensions).

By allowing you to set the traffic requirements with the OpenAPI 3.0 specification, Wallarm API Firewall relies on a positive security model.

Technical characteristics

API Firewall works as a reverse proxy with a built-in OpenAPI 3.0 request and response validator. The validator is written in Go and optimized for extreme performance and near-zero added latency.

Quick start with Docker

This quick start guide walks through downloading and starting Wallarm API Firewall with minimal configuration on Docker.

Requirements

Up and running

To run Wallarm API Firewall with minimal configuration on Docker:

  1. Create the Docker network to connect your application and Wallarm API Firewall (e.g. api-firewall-network):

    docker network create api-firewall-network
    
  2. Start the containerized application to be protected with API Firewall (e.g. kennethreitz/httpbin):

    docker run --rm -it --network api-firewall-network \
        --network-alias backend -p 8090:8090 kennethreitz/httpbin
    
  3. Start the API Firewall image:

    docker run --rm -it --network api-firewall-network --network-alias api-firewall \
        -v <HOST_PATH_TO_SPEC>:<CONTAINER_PATH_TO_SPEC> -e APIFW_API_SPECS=<PATH_TO_MOUNTED_SPEC> \
        -e APIFW_URL=<API_FIREWALL_URL> -e APIFW_SERVER_URL=<PROTECTED_APP_URL> \
        -e APIFW_REQUEST_VALIDATION=<REQUEST_VALIDATION_MODE> -e APIFW_RESPONSE_VALIDATION=<RESPONSE_VALIDATION_MODE> \
        -p 8088:8088 wallarm/api-firewall:v0.6.4
    
    Variables Description
    For the -v option
    <HOST_PATH_TO_SPEC> The path to the OpenAPI 3.0 specification for your application REST API located on the host machine. The accepted file formats are YAML and JSON (.yaml, .yml, .json file extensions). For example: /opt/my-api/openapi3/swagger.json.
    <CONTAINER_PATH_TO_SPEC> The path to the container directory to mount the OpenAPI 3.0 specification to. For example: /api-firewall/resources/swagger.json.
    For the -e option
    APIFW_API_SPECS Path to the OpenAPI 3.0 specification mounted to the container. For example: /api-firewall/resources/swagger.json.
    APIFW_URL URL for API Firewall. For example: http://0.0.0.0:8088/. The port value should correspond to the container port published to the host.
    APIFW_SERVER_URL URL of the application described in the mounted OpenAPI specification that should be protected with API Firewall. For example: http://backend:80.
    APIFW_REQUEST_VALIDATION API Firewall mode when validating requests sent to the application URL:
    • BLOCK to block and log the requests that do not match the schema provided in the mounted OpenAPI 3.0 specification (the 403 Forbidden response will be returned to the blocked requests). Logs are sent to the STDOUT and STDERR Docker services.
    • LOG_ONLY to log but not block the requests that do not match the schema provided in the mounted OpenAPI 3.0 specification. Logs are sent to the STDOUT and STDERR Docker services.
    • DISABLE to disable request validation.
    APIFW_RESPONSE_VALIDATION API Firewall mode when validating application responses to incoming requests:
    • BLOCK to block and log the request if the application response to this request does not match the schema provided in the mounted OpenAPI 3.0 specification. This request will be proxied to the application URL but the client will receive the 403 Forbidden response. Logs are sent to the STDOUT and STDERR Docker services.
    • LOG_ONLY to log but not block the request if the application response to this request does not match the schema provided in the mounted OpenAPI 3.0 specification. Logs are sent to the STDOUT and STDERR Docker services.
    • DISABLE to disable request validation.
  4. Test API Firewall operation by sending the request that does not match the mounted Open API 3.0 specification to the API Firewall Docker container address. For example, you can pass the string value in the parameter that requires the integer value.

    If the request does not match the provided API schema, the appropriate ERROR message will be added to the API Firewall Docker container logs.

You have successfully started Wallarm API Firewall with minimal configuration. To learn advanced configuration options, please use the separate instructions on running Wallarm API Firewall with Docker.

Demos

You can try API Firewall by running the demo environment that deploys an example application protected with Wallarm API Firewall. There are two available demo environments: