Project of Reverse Engineering LINE Messaging App (for education purpose)
This project was carried out in order to obtain and make the thrift file of LINE Thrift Protocol (client-side).
And also, feel free to contribute ๐
Before doing this, you need to have this on you:
- Java 1.8 or greater (Get it here)
- Thrift types understanding on a compiled thrift (Read this)
- Some apk decompiler (I'm using jadx)
- A
littlegood understanding of java
This is how i obtain the thrift file and make it human-readable form:
- Download LINE App from playstore using downloader like Evozi
- If you're downloading a new version of LINE (maybe version 8 or greater), you'll get zip file instead of apk file. Don't worry, just extract the file and you'll find the apk (jp.naver.line.android.apk)
- Decompile apk using your decompiler (you have to decompile it into a java file)
- Now search for the
new TStruct("thisIsStruct")
code in a *.java file- But that's not an easy thing to do, the
new TStruct("thisIsStruct")
is definitely obfuscated by the developer and it can be something like thisnew A340v("thisIsStruct")
. You have to figure it out by yourself
- But that's not an easy thing to do, the
- And the result must be like this (if you're using jadx)
- Now just click one of the result with
_args
in it, and you'll be redirected to the package sourceverifyEapLogin
is the struct namenew C6282b(arg1,arg2,arg3)
is a struct field builder, but you see that it have 3 arguments. So here is the explanation :OAuthWebLoginServiceActivity.f1422071
is a field name (should be string), but we got something like that. Because of the name is not a string, you have to explore theOAuthWebLoginServiceActivity.f1422071
to get the name.(byte) 12
is a type of a field. (12 = struct)1
is the id of a field.
- After that, you have to scroll down a little bit and you'll get like this
- And now you can make it into human-readable form, the result must be like this
RESPONSETYPE_STRUCT verifyEapLogin(1: OAUTHACTIVITY_STRUCT field_name) throws(1: EXCEPTION_STRUCT e)
- So, that's how to obtain and build LINE Thrift Protocol (client-side)