Usage of Reverse Engineering/Rebuilding an APK

Question

Recently I've been trying apktool but I wonder what is the use of reverse engineering/rebuilding an APK with a tool like apktool? I've already searched it but I didn't find the answer

Answer 1

You'll find different reasons for many people.

• Static analysis - Investigating an application for an audit, looking for malicious behavior or running analytics at scale against large collections of applications. It is easier to query an application disassembled via Apktool (at times) then talking directly to a compiled APK.
• Automation - Before the constant improvements to tooling in the Android space, it was quite favorable to rename a package name through Apktool. This may be part of a build process to make a quick "test" application with security enhancements disabled to make debugging/logging easier.
• Reverse Engineering - See how something works, take apart a malware sample. The possibilities in this category are quite broad.
• Translation - Lots of applications are built from afar and some folks are interested enough in ROMs, Apps and more to make them usable for their culture/language. A simple disassemble and rebuild with newer language files and the application is translated.
• Tweaking - At times an application is almost perfect for an individual. They don't trust updates and want to make a quick change to an application and run it themselves without poking around in assembled files.
• Abuse - Taking paid features out of paid applications and rehosting them. Not happy about this one, but can't ignore it happens