Setting up the environment for decompiling Android apps on Mac OS

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Often, for the purpose of learning or security testing, we need to decompile the installation files of the Android app to view the source code. Let's build a decompilation environment under Mac OS.

Installation Environment

Create a basic folder

mkdir -p ~/study/apkkiller/soft/bin

mkdir -p ~/study/apkkiller/soft/src

mkdir -p ~/study/apkkiller/output/

The installation file of andorid app is apk package. To decompile apk file, you need to download apktool and dex2jar, both of which are hosted on google code:

http://code.google.com/p/android-apktool/

http://code.google.com/p/dex2jar/

Find the download address from the above two pages. Here we find the download address of apktool1.5.2 and dex2jar-0.0.9.15:

cd ~/study/apkkiller/soft/src

wget http://android-apktool.googlecode.com/files/apktool1.5.2.tar.bz2

wget http://dex2jar.googlecode.com/files/dex2jar-0.0.9.15.zip

The decompressed files are stored in the following directory:

~/study/apkkiller/soft/src/apktool1.5.2

~/study/apkkiller/soft/src/dex2jar-0.0.9.15

For ease of use, create two soft links:

ln -s ~/study/apkkiller/soft/src/apktool1.5.2/apktool.jar ~/study/apkkiller/soft/bin/apktool

ln -s ~/study/apkkiller/soft/src/dex2jar-0.0.9.15/dex2jar.sh ~/study/apkkiller/soft/bin/dex2jar

Test decompilation environment

Let's start decompiling our test apk file to see if the environment can run normally

 cd ~/study/apkkiller
 mkdir -p ~/study/apkkiller/output/test/source
 mkdir -p ~/study/apkkiller/output/test/result 
 
 cp ./test.apk ./output/test/source/test.zip
 unzip ./output/test/source/test.zip -d ./output/test/source/test 
 
 cp ./output/test/source/test/classes.dex ./output/test/source/classes.dex
 ~/study/apkkiller/soft/bin/dex2jar ./output/test/source/classes.dex
 # output ./output/test/source/classes_dex2jar.jar

To view the decompiled files, you can download the jd-gui tool and open the ./output/test/source/classes_dex2jar.jar file generated above. This tool can export all the source code packages. Download jd-gui from the following address:

http://jd.benow.ca/

http://jd.benow.ca/jd-gui/downloads/jd-gui-0.3.5.osx.i686.dmg

The apk resource files are stored in the folder ./output/test/source/test that we unzipped above. There are many xml files in it, but they are encrypted and cannot be viewed directly. At this time, you need to use the apktool tool:

java -jar ~/study/apkkiller/soft/bin/apktool d ./test.apk ./output/test/source/test_resource

Merge the exported source code and resource files to get the result we want.