Reverse Engineering the Enphase Installer Toolkit

If you are interested in other Enphase information the following other pages may also be of interest:
What is inside the Enphase Envoy-S (teardown)
Enphase Envoy-S “Data Scraping”.
Enphase Envoy-S Open Ports!

While on my quest to create my own logging and analytics for the Envoy-S Solar PV controller I also was interested in how the Installer Toolkit authenticates with the web interface of the Envoy.

Authentication is “Digest” based so it isn’t as simple as just undoing the base64 encoding that “Basic” http authentication uses. Digest uses a nonce, domain and url in the mix to make each request to different pages need it’s own hashed password.

The trouble is – I don’t know what the password is for the Envoy. The username is “installer” but the password isn’t something known. I hoped to extract the password generation method from the Android application.

What helped is the fact that it seems the application is a Xamarin based application. As far as I can work out this means they wrote the application in Microsoft Visual Studio and have ported it to run on multiple mobile devices (Apple, Android, Windows Phone(?)).

So – decompressing the APK produces a load of windows .dll files! ILSpy then allows me to investigate the content or code within.

So.. all easy for me to understand in the language(s) that I can work with.
Imagine my surprise when I came across the “Configuration” section.

Private Const OAuth2BogusClientId As String = "installer-toolkit-bogus"

Private Const OAuth2BogusSecret As String = "911wasaninsidejob"

Private Const OAuth1BogusConsumerKey As String = "notavalidconsomerkey"

Private Const OAuth1BogusConsumerSecret As String = "Oauth1911wasaninsidejob"

While being part of code that isn’t used in active connections (I believe the bogus sections are for offline, debug or demonstration testing that don’t authenticate against live systems).. I’m amazed that wording like that has remained within a program written by a company who, I presume, wouldn’t like it against their reputation.

My first thought is maybe a programmer has taken example code and forgotten to change the strings.. but no, a quick Google Search doesn’t reveal any pages at all with the wording in it… so it isn’t a lazy copy and paste from existing public “example” code.

Moving on from that… Other interesting bits of code are:

Public Function UsernameIsReviewUser(username As String) As Boolean
    Return Not String.IsNullOrEmpty(username) AndAlso username.ToLower().Equals("enphase.rev1400@gmail.com")
End Function
Friend Module Crypto
    Private salt As Byte() = Encoding.ASCII.GetBytes("com.enphase-energy.rocksit247")

If you are on Android then the SQLite Database it uses is stored in “/mnt/sdcard/Enphase/EnphaseDB_fixed.db3”.

When the Envoy is in AP mode the IP address might be  “172.30.1.1”

Back onto Task. The Digest Authentication is handled by “Enphase.InstallerToolkit -> Enphase.Installeroolkit.Models -> EnphaseEnvoy” and uses the following code:

Public Sub SetupAuth()
	Dim credentialCache As CredentialCache = New CredentialCache()
	credentialCache.Add(New Uri("http://" + Me.IP_Address), "Digest", New NetworkCredential("installer", Me.GetPasswordForEnvoy()))
	credentialCache.Add(New Uri("http://" + Me.IP_Address + ":9094"), "Digest", New NetworkCredential("installer", Me.GetPasswordForEnvoy()))
	Dim nativeCookieHandler As NativeCookieHandler = New NativeCookieHandler()
	Dim list As List(Of Cookie) = New List(Of Cookie)()
	For Each current As Cookie In nativeCookieHandler.Cookies
		If current.Name.ToUpper().Equals("SESSIONID") Then
			current.Value = Nothing
			list.Add(current)
		End If
	Next
	nativeCookieHandler.SetCookies(list)
	Me.httpClient = New HttpClient(New NativeMessageHandler(False, False, nativeCookieHandler) With { .UseDefaultCredentials = False, .Credentials = credentialCache })
End Sub

Public Function GetPasswordForEnvoy() As String
	Dim bufLen As UInteger = 128UI
	Dim stringBuilder As StringBuilder = New StringBuilder(128)
	EnphaseEnvoy.emupwGetMobilePasswd(Me.Serial_Number, "installer", Nothing, stringBuilder, bufLen)
	Return stringBuilder.ToString()
End Function

Public Shared Declare Function emupwGetMobilePasswd Lib "libemupw.so" (in_serialNumber As String, in_user As String, in_domain As String, out_buf As StringBuilder, bufLen As UInteger) As Integer 

In plain terms this means the function “SetupAuth” adds credentials to the http request using the hard coded username “installer” and the password generated by the function ” GetPasswordForEnvoy”.

GetPasswordForEnvoy, as far as I can read, creates a 128 character buffer and string and then requests another function of “emupwGetMobilePasswd” with the parameters:
Serial Number of Envoy, “installer”, Nothing, Blank String, Blank Buffer

Now; emupwGetMobilePasswd then references to an external “libemupw.so”dependent which appears to be a compiled program or component for ARM architecture processors. Sadly it doesn’t seem to be a drop in component and is likely a custom file for Enphase
It only seems to take the serial number and username as input. The “Domain” string (3rd input) is set to “Nothing” in the code and the final two variables are the out string and buffer.

This is where it gets beyond me skill level. I will continue to research and work out how I can either run the object on demand or just the math or function used to hash the details to return the password. More to come.. Bookmark and return at some point.

Update: 19th November 2016. Version 2.1.10 of the Installer Toolkit is out and has the following notable changes.

It contains a variable WORK_OFFLINE_KEY

Update: 21st August 2018. My own password cracked!

I’ve finally managed to make my own software that can interface with the libemupw.so file mentioned above! I can now, on demand, generate passwords against Envoy-S serial numbers.

I need to investigate if I can either package it up and distribute it for others to generate their own passwords or if I can make it a web based password generator somehow. The biggest problem is the .so is compiled for ARM… so getting data into and out of it will require an ARM emulator or a mobile phone.

Success.. web access to the installer interface on a computer!

Update: 22nd August 2018. Application made!

Enphase Energy Envoy-S password algorithm runner app!

You can download the Android app here.. Install then run it.. type in your units serial number and the blue box will show the installer password!

Update July 2021: A phyton script appears!
A visitor has managed to do what I couldn’t and has re-written the functions (my method just “uses” the existing compiled dll; hence the android requirement).
https://github.com/sarnau/EnphaseEnergy
Please show your gratitude by commenting below saying thanks if you use either method.