baby-android-1 - ByuCTF Writeup

Challenge Info

Field	Details
CTF	ByuCTF
Challenge	baby-android-1
Category	Android / Reverse Engineering

Solution

We can begin by inspecting the Manifest file

Nothing much in the manifest, only one activity

The Main activity does nothing but call the Utils.cleanUp() method And if we inspect Utils Class

Same as the name, Utils.cleanUp() cleans the text in the textviews and sets it to nothing If we search the flagpart* in the resources file,

1. Inside strings.xml theres nothing there
2. But in layout/activity_main.xml file, we see:

Every text view has one char in it has a text If we assemble it by order we get, b{e4_if_e_efcopukd0inrdccyat} but this does not make any sense Every textview has a definite position in the layout, So we can just copy paste the textviews to our POC app to see how it will look

Even though, it is distorted we can read it to :

Flag

Flag : byuctf{android_piece_0f_c4ke}