Add the initial ngrok docs

Author: zeroSteiner

docs/metasploit-framework.wiki/How-to-use-Metasploit-with-Ngrok.md

@@ -0,0 +1,44 @@
+# Overview
+[ngrok][1] is a popular service that offers free port-forwarding that is easy to setup without needing to run a
+dedicated server on a public IP address (as is the case with SSH, socat and other more traditional options. This means
+that users behind a SNATing device such as a SOHO router can accept reverse shells and other connections without needing
+to configure port forwarding.
+
+**WARNING:** The nature of using ngrok is to send traffic through a third party. ngrok and the server which it utilizes
+are not affiliated with the Metasploit project. Use of ngrok effectively sends traffic through an untrusted third party
+and should be done with extreme caution. While Meterpreter has offered end-to-end encryption since Metasploit 6.0, other
+payloads and connections do not.
+
+ngrok can start multiple types of tunnels. The `tcp` tunnel is compatible with Metasploit's payloads and most closely
+resembles a traditional port-forwarding configuration. The `http` tunnel type is not compatible with payloads, and
+should not be used. The `tls` tunnel type may be compatible, but access to it is restricted to the Enterprise and 
+Pay-as-you-go paid plans. This document will focus on the use cases for the `tcp` tunnel type. Note that one limitation
+is that the public port can not be configured, it is randomly selected by ngrok meaning that the target will need to be
+able to connect to this high, obscure port which may be prevented by egress filtering.
+
+## Usage with payloads
+Use with payloads can be achieved with any of the reverse-connection stagers that accept `LHOST` and `LPORT` options,
+e.g. reverse_tcp, reverse_http, reverse_https, etc. but not reverse_named_pipe. In the following scenario, ngrok will be
+used to forward a random public port to the Metasploit listener on port 4444. This scenario assumes that Metasploit and
+ngrok are running on the same host.
+
+1. Start a TCP tunnel using ngrok: `ngrok tcp localhost:4444`.
+1. ngrok should start running and display a few settings, including a line that says "Forwarding". Note the host and IP
+   address from this line, e.g. `4.tcp.ngrok.io:13779`
+1. Start msfconsole and use the desired payload or exploit module.
+  * Using `msfconsole` for both generating the payload and handling the connection is recommended over using `msfvenom`
+    for two reasons.
+    1. Using `msfvenom` starts up an instance of the framework to generate the payload, making it a slower process.
+    2. Using `msfconsole` to configure both the payload and handler simultaneously ensures that the options are set for
+       both, eliminating the possibility that they are out of sync.
+1. Set the `LHOST` option to the address noted in step 2, `4.tcp.ngrok.io` in the example. This is where the payload is
+   expecting to connect to.
+1. Set the `LPORT` option to the port noted in step 2, `13779` in the example.
+1. Set the `ReverseListenerBindAddress` option to `127.0.0.1`. This is where the connection will actually be accepted
+   from ngrok.
+1. Set the `ReverseListenerBindPort` option to `4444`.
+1. Either run the exploit, or generate the payload with the `generate` command and start the handler with `to_handler`
+
+
+
+[1]: https://ngrok.com/

docs/navigation.rb

@@ -445,6 +445,9 @@ def without_prefix(prefix)
           {
             path: 'How-to-use-the-Favorite-command.md'
           },
+          {
+            path: 'How-to-use-Metasploit-with-Ngrok.md'
+          },
         ]
       },
     ]