It absolutely will, I thought you just meant repacking it, which is what I just described, what you're talking about is more like rewriting.
The answer to that is that they use a tool to modify the bytecode. You can use a few options: convert it to java bytecode, do the mods, and then convert back via dex, or manipulate the bytecode directly. There are a bunch of tools that do this, baksmali is also a popular choice for disassembly. You can google around to find tools that meet your needs, but I've also worked on a binary rewriter for Android that is relatively mature: https://github.com/plum-umd/redexer Kris On Wed, May 22, 2013 at 5:18 PM, Ishan Sharma <[email protected]> wrote: > But the .dex file is in byte code which has a certain structure. If we > manipulate that .dex file won't it break the code? > > > On Thu, May 23, 2013 at 1:40 AM, Kristopher Micinski > <[email protected]> wrote: >> >> The APK is simply a zip file: nothing more. >> >> It's pretty typical to take a legitimate app and unzip it, add some >> code, and repacking it (just zipping it up as an APK). >> >> There's not really much to add, the standard tools in the Android SDK >> do all of this for you, >> >> Kris >> >> On Wed, May 22, 2013 at 12:39 PM, Ishan Sharma <[email protected]> >> wrote: >> > Is there anyone who can help? >> > >> > Thanks! >> > >> > On Sat, May 18, 2013 at 10:46 PM, Ishan Sharma >> > <[email protected]> >> > wrote: >> >> >> >> Hello! >> >> >> >> I am a research student working on Android Security. I have been >> >> reading >> >> some research papers related to android malwares and all the research >> >> papers >> >> mention that most of the malware is developed by "repackaging" a benign >> >> binary. There have also been research papers to detect repackaged >> >> applications. Could someone please tell me what is .apk file >> >> repackaging >> >> (binary repackaging). Also how can I repackage .apk files? Since they >> >> are >> >> binary files any modification done to them could break the application. >> >> >> >> Any links etc. which explain how to perform .apk file repackaging will >> >> also be very good. >> >> >> >> >> >> Thanks >> >> >> >> -- >> >> -- >> >> You received this message because you are subscribed to the Google >> >> Groups "Android Developers" group. >> >> To post to this group, send email to >> >> [email protected] >> >> To unsubscribe from this group, send email to >> >> [email protected] >> >> For more options, visit this group at >> >> http://groups.google.com/group/android-developers?hl=en >> >> --- >> >> You received this message because you are subscribed to a topic in the >> >> Google Groups "Android Developers" group. >> >> To unsubscribe from this topic, visit >> >> >> >> https://groups.google.com/d/topic/android-developers/mG2ON1L3IHg/unsubscribe?hl=en. >> >> To unsubscribe from this group and all its topics, send an email to >> >> [email protected]. >> >> >> >> For more options, visit https://groups.google.com/groups/opt_out. >> >> >> >> >> > >> > >> > -- >> > -- >> > You received this message because you are subscribed to the Google >> > Groups "Android Developers" group. >> > To post to this group, send email to [email protected] >> > To unsubscribe from this group, send email to >> > [email protected] >> > For more options, visit this group at >> > http://groups.google.com/group/android-developers?hl=en >> > --- >> > You received this message because you are subscribed to the Google >> > Groups >> > "Android Developers" group. >> > To unsubscribe from this group and stop receiving emails from it, send >> > an >> > email to [email protected]. >> > For more options, visit https://groups.google.com/groups/opt_out. >> > >> > >> >> -- >> -- >> You received this message because you are subscribed to the Google >> Groups "Android Developers" group. >> To post to this group, send email to [email protected] >> To unsubscribe from this group, send email to >> [email protected] >> For more options, visit this group at >> http://groups.google.com/group/android-developers?hl=en >> --- >> You received this message because you are subscribed to a topic in the >> Google Groups "Android Developers" group. >> To unsubscribe from this topic, visit >> https://groups.google.com/d/topic/android-developers/mG2ON1L3IHg/unsubscribe?hl=en. >> To unsubscribe from this group and all its topics, send an email to >> [email protected]. >> For more options, visit https://groups.google.com/groups/opt_out. >> >> > > -- > -- > You received this message because you are subscribed to the Google > Groups "Android Developers" group. > To post to this group, send email to [email protected] > To unsubscribe from this group, send email to > [email protected] > For more options, visit this group at > http://groups.google.com/group/android-developers?hl=en > --- > You received this message because you are subscribed to the Google Groups > "Android Developers" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/groups/opt_out. > > -- -- You received this message because you are subscribed to the Google Groups "Android Developers" group. 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