added details about API Gateway

Enumeration/AWS.md

@@ -1467,9 +1467,43 @@ An HTTP API consists of the following parts.
 * Specific HTTP headers
 * HTTP Method
 * Endpoint the request is queried
- 
-There is an option for real-time, bidirectional websocket connection.
 
-Lambda acts as a service proxy. The API Gateway can be attached to other AWS resources, e.g. Lambda. The Lambda authorizer can be used to check for credentials to other resources.
+It acts as a serverless reverse proxy for other APIs.
+There is an option for real-time, bidirectional websocket connection, besides
+regular RESTlike HTTP(S) APIs.
 
+Monitoring is an integrated part of the Gateway.
+
+Data the API Gateway uses is stored in an S3 bucket or a DynamoDB.
+
+Microservices can be used through the API Gateway as well.
+
+#### Lambda Authorizer
+
+Lambda acts as a service proxy for the API Gateway. The API Gateway can be
+attached to other AWS resources, e.g. Lambda. The Lambda authorizer can be used
+to check for credentials to other resources. Authorization can be done via
+regular IAM or OAuth2. The authorization can be customized for access.
+
+A policy is set for authorization against resources. Watch out for `*` wildcards
+inside these Lambda authorizer policies to get unexpected permissions.
+
+#### Use an API Gateway as a Reverse Proxy
+
+Rotation of IP addresses for an attack may bypass restrictions, like rate-limiting, set for an address.
+This can be done via VPNs, e.g. Tor or more suitable in this case using the AWS
+API Gateway to rotate the IP address via FireProx. 
+
+Use the Cloudshell inside a browser to clone and install the [Fireprox repository](https://github.com/ustayready/fireprox). Start `fire.py` afterwards.
+
+You can use Fireprox externally from the AWS, but you have set an endpoint via a URL to achieve a connection.
+
+```sh
+./fire.py --command create --url <URL>
+```
+
+Using any of these two lets you list existing APIs.
+
+```sh
+./fire.py --command list