This project is in no way associated with LernSax, WebWeaver, DigiOnline GmbH or Freistaat Sachsen

Description

This is a modification for the lernsax android app (and probarly other webweaver apps too) that integrates IGLogger into the app. This allows the user to watch the requests between the android device and the json_rpc api of the LernSax/WebWeaver servers. This can be helpful for the reverse engineering and documentation of the json_rpc lernsax api. If you want to look at the already existing documentation, want to share dumps or want to share you knowledge you can take look at my own research repository.

Usage

Using logcat you will see every request that the lernsax app makes marked as LernLog.REQ and every response it gets as LernLog.RESP.

Installation

Requirements

lernsax This probarly works with other WebWeaver based apps too but I couldn't try it out yet.
apkextractor
apktool
iglogger.smali
JsonApiTask.diff
java jdk

only required for windows

patch

Steps

1. Install LernSax on your phone.
2. Use APKExtractor to create the lernsax.apk
3. Transfer the apk to your PC.
4. Decode the apk using apktool
   apktool d -o "lernsaxdecoded" lernsax.apk
5. Rename the iglogger file to iglogger.smali if you haven't already
6. Copy the iglogger.smali to lernsaxdecoded/smali/de/digionline/webweaver/api/tasks
7. Patch the JsonApiTask.smali
   patch lernsaxdecoded/smali/de/digionline/webweaver/api/tasks/JsonApiTask.smali JsonApiTask.diff
8. Build the patched apk
   apktool b -o lernsaxpatched.apk lernsaxdecoded
9. Create a key for signing
   keytool -genkey -v -keystore my-release-key.keystore -alias alias_name -keyalg RSA -keysize 2048 -validity 10000
10. Sign the apk with the key
    jarsigner -verbose -sigalg SHA1withRSA -digestalg SHA1 -keystore my-release-key.keystore lernsaxpatched.apk alias_name
11. Transfer the apk to your device.
12. Uninstall the lernsax app.
13. Install the patched apk.
14. Activate USB Debugging
15. Use logcat to watch the log
16. profit!