GreHack-2012/100-GrehAndroidMe-apk

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GreHack-2012

100-GrehAndroidMe.apk

Description

CTF

GreHack CTF 2012 reverse engineering challenge (100 points).

Installation

mobisec@ubuntu:/opt/mobisec/Android/sdk/platform-tools$ ./adb -s emulator-5554 install /data/grehack/GrehAndroidMe.apk 
994 KB/s (61622 bytes in 0.060s)
        pkg: /data/local/tmp/GrehAndroidMe.apk
Success

The Android application looks like this:

Basic identification

apktool

$ java -jar apktool_2.0.1.jar d GrehAndroidMe.apk 
I: Using Apktool 2.0.1 on GrehAndroidMe.apk
I: Loading resource table...
I: Decoding AndroidManifest.xml with resources...
I: Loading resource table from file: /home/unknown/apktool/framework/1.apk
I: Regular manifest package...
I: Decoding file-resources...
I: Decoding values */* XMLs...
I: Baksmaling classes.dex...
I: Copying assets and libs...
I: Copying unknown files...
I: Copying original files...

$ grep activity AndroidManifest.xml 
        <activity android:label="@string/title_activity_main" android:name=".MainActivity">
        </activity>

dex2jar

$ ./d2j-dex2jar.sh GrehAndroidMe.apk 
dex2jar GrehAndroidMe.apk -> ./GrehAndroidMe-dex2jar.jar

$ ./jd-gui GrehAndroidMe-dex2jar.jar 

JD-GUI shows the following classes:

• MainActivity.class
• a.class
• b.class
• c.class
• d.class

Comments

Keywords: grehack-2012 reverse-engineering crackme android apk