apk_api_key_extractor

Automatically extracts API Keys from APK (Android Package) files

For technical details, check out my thesis (Automatic extraction of API Keys from Android applications) and, in particular, Chapter 3 and 4 of the work.

The library responsible for identifying the API Keys is a standalone project.

Searches for API Keys embedded in Android String Resources, Manifest metadata, Java code (included Gradle's BuildConfig), Native code.

Requirements

• Java 7+
• Python 3.5+
• Modules in requirements.txt (use pip3 to install)

pip3 install -r requirements.txt

Installation

$ git clone --recursive https://github.com/alessandrodd/apk_api_key_extractor.git
$ cd apk_api_key_extractor
$ cp config.example.yml config.yml
$ pip3 install -r requirements.txt
$ python3 main.py

Test

$ git clone https://github.com/alessandrodd/ApiKeyTestApp.git
$ cd apk_api_key_extractor
$ python3 main.py --analyze-apk ../ApiKeyTestApp/apk/apikeytestapp_obfuscated.apk

Usage

usage: main.py [-h] [--debug] [--analyze-apk APK_PATH] [--monitor-apks-folder]

A python program that finds API-KEYS and secrets hidden inside strings

optional arguments:
  -h, --help            show this help message and exit
  --debug               Print debug information
  --analyze-apk APK_PATH
                        Analyze a single apk to find hidden API Keys
  --monitor-apks-folder
                        Monitors the configured apks folder for new apks. When
                        a new apk is detected, the file is locked and analysis
                        starts.

Let's say you want to find any API Key hidden inside a set of Android apps.

Using the default settings:

• Copy all the desired .apk files to the apks folder
• Start apk_api_key_extractor with the monitor-apks-folder argument, i.e. : python3 main.py --monitor-apks-folder
• Check the apikeys.json file for detected API Keys
• As soon as an apk is analyzed, it gets moved from the apks to the apks_analyzed folder

Note that this software is process-safe, meaning that you can start multiple instances of the same script without conflicts. You can also configure the apks folder as a remote folder in a Network File System (NFS) to parallelize the analysis on multiple hosts.

Run in a docker container

NOTE: make sure your .APK file is in the 'apks' folder.

$ git clone --recursive https://github.com/alessandrodd/apk_api_key_extractor.git
$ cd apk_api_key_extractor
$ docker build -t apk_key_extractor:latest .
$ docker run -it apk_key_extractor:latest

Rebuild your image when you've added other .apk's in your 'apks' folder.

Config File Explained

config.yml

apks_dir => The folder containing the .apk files to be analyzed

apks_decoded_dir => The folder that will temporarily contain the decompiled apk files

apks_analyzed_dir => The folder that will contain the already analyzed .apk files. Each time an APK is analyzed, it gets moved from the apks_folder to this folder

save_analyzed_apks => If false, the .apk files gets removed instead of being moved to the apks_analyzed folder

apktool => Path of the main apktool jar file, used to decode the apks

lib_blacklists => Txt files containing names of the native libraries (one for each line) that should be ignored during the analysis

shared_object_sections => When analyzing native libraries, all the ELF sections listed here will be searched for API Keys

dump_all_strings => If true, the script dumps not only API Keys but also every other string found in the APK. Useful to make a dataset of common not-api-key strings that can be used to train the model itself.

dump_location => Where to dump the API Keys found (as well as every other strin, if dump_all_strings is set to true). Possible values are console (stdout), jsonlines (text files in the jsonlines format), mongodb.

jsonlines.dump_file => Path of the jsonlines file where the API Keys will be dumped

jsonlines.strings_file => Path of the jsonlines file where the every string will be dumped, if dump_all_strings is true

mongodb.name => Used if key_dump is set to mongodb; name of the MongoDB database

mongodb.address => Address of the MongoDB database

mongodb.port => Port to which to contact the MongoDB database (default 27017)

mongodb.user => MongoDB database credentials

mongodb.password => MongoDB database credentials

Notes

I'm a curious guy; if you make something cool with this and you want to tell me, drop me an email at didiego.alessandro+keyextract (domain is gmail.com)