Questions tagged [ios]

The operating system by apple for mobile devices

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1 answer
86 views

strange arm construct in objective-c application

I was reversing the objective-c application and stumbled upon an assembler construction that I don't understand: This is call of some function with SP register (+ 0x18 offset) as parameter. (Picture1)....
1 vote
0 answers
36 views

IOS ASLR address calculation with delta offset (ARM64)

I am learning LLDB to debug ios apps, I have a jailbroken iPhone IOS 14.3 and a debugserver. Screenshot of start connect to remote process: Sections of my process(image dump sections hidenseek): ...
0 votes
1 answer
6k views

how should i change an instruction to NOP in IDA?

I am new with IDA assembler and i used to work with hopper app. the problem is i can't change instruction in IDA from something like CBNZ to NOP. is there any button to do this? i can't find anything ...
1 vote
0 answers
36 views

how to find a string in memory having ARM instructions ARDP and LDR?

hello, I disassembled the request sent to the game server, I need to change the symbol, but I don’t know its memory address. Help me understand the ADRP and LDR instructions, I need to understand what ...
2 votes
0 answers
33 views

Trying to understand a simple compiled PSI binary file

I was working with an old ios game, and found that it saved most of its data (players, worlds, anything in-between) in MDB files.. titled data.mdb and lock.mdb. There is a pair for every object type (...
0 votes
1 answer
100 views

Is iOS 15 kernel cache encrypted?

I recently started researching ios kernel security and I've been struggling to find out whether the kernel cache is encrypted for iOS 15. Any help would be really appreciated.
4 votes
1 answer
216 views

Reverse engineer compressed iOS app file

I want to find out the compression method used by an iOS app used for music notation to store its files. The files of its OSX counterpart are zipped files. You cannot create files in the iOS app, but ...
1 vote
1 answer
95 views

What kind of random algorithm is used in this game?

I am playing a game for iOS that uses a deck of 48 cards and I would like to reverse engineer the kind of algorithm that is used to generate the random deck of cards such that I can predict which card ...
0 votes
0 answers
30 views

iOS unknown library sending ssl pinned request

Here is my problem: I am trying to access to a ssl pinned request sent by an action I am doing on an iPhone. The action I am making sends two requests: The first one is ssl pinned, sent by a pre-...
1 vote
1 answer
92 views

Create instance of iOS class that contains a . with frida

I am trying to create an instance of a class of an iOS app using Frida. In the past I have successfully done this using a command such as: var instance = ObjC.chooseSync(ObjC.classes.TestClass)[0]; ...
2 votes
1 answer
3k views

Using IDA Pro, How can I just "edit" values, Rather than patching Offsets,

I dont understand how people are finding offsets, So I want to know if there's a simple and easy method of just "patching values" I've been surfing the internet looking for VERY in depth ...
1 vote
0 answers
108 views

Backtrace HTTP request over few modules when using FRIDA

I am in the process of reverse engineering an IOS IPA using HOPPER and FRIDA. First, I started with POSTMAN, which records the app's HTTP requests. What I find interesting is that the app uses a so-...
1 vote
0 answers
135 views

How to get variable value during IDA (Hex-Rays Decompiler) debugging?

I'm debugging a iOS App by IDA, and I need to see the value of some var like v57 below. Through the Locals panel know the value is 0x1137D0E00LL, but I want to see the real value or class. How to get ...
64 votes
7 answers
130k views

What are the possibilities for reverse engineering an IPA file to its source?

I browsed a lot, but can't find any resources for reverse engineering an IPA file (iPhone application). Is there any method to reverse engineer an IPA file to its source? I've tried to rename it to ...
0 votes
0 answers
25 views

Change function implementation

I have a Mach-O 64-bit dynamically linked shared library (ARM64), wrote in Swift/Objective-C language for iOS. Is theoretically possible to open this file in Ghidra or IDA reverse tool, change some ...
0 votes
0 answers
47 views

Is there any way to extract sandbox bundles since the implementation of monolithic kernelcaches?

I'm trying to obtain the same result that joker -K <bundle> <kernelcache> used to obtain. I tried using jtool2, but it appears that when I'm trying to extract a bundle nothing happens when ...
1 vote
1 answer
117 views

Change iOS app binary file

I want to manipulate iOS binary file and change two strings in it. I used hex editor to search and change these strings. But after the binary file is uploaded and replaced with the origin app's binary ...
1 vote
0 answers
126 views

Int64 parsing from args in Frida-trace for iOS binaries

I'm using frida-trace to log some methods and I've come across the following. onEnter(log, args, state) { log(`-[Somefunction somefield64:${args[2]}]`) } somefield64 returns what I believe to ...
1 vote
0 answers
351 views

How are strokes stored in the Goodnotes file format?

I have been trying to reverse engineer the .goodnotes file format (a note taking app for iOS devices) and so far have discovered this: A .goodnotes file is simply a zip archive, an example file ...
5 votes
2 answers
9k views

OTOOL alternative for linux

I have a reverse engineering set up on a Mac machine. This set up does some reverse engineering on iOS applications(.ipa files). I'm migrating the setup from Mac to a linux machine. Currently on Mac, ...
2 votes
1 answer
699 views

Read and write to register with Frida

I have an instruction that looks like this in Ghidra: 100168ff0 e9 13 00 32 orr w9,wzr,#0x1f Using lldb I can set a breakpoint on the instruction after this, read w9 to confirm what ...
2 votes
2 answers
547 views

Attempting to reverse engineer an iOS OTA payload-like archival format

Apple's announcement of macOS Big Sur had meant the release of the developer beta. In an attempt to create the appbundle from Apple's softwarecatalog, I attempted to study the contents of ...
0 votes
2 answers
68 views

How to calculate the value needed to branch two points in IDA pro?

I need to find how to get the value to make a branch between two points in IDA Pro, but I can’t figure it out. For more context: the instructions I’m following says “Calculate the value needed to do a ...
0 votes
1 answer
193 views

Why the disassembled code in IDA is different from in xcode? And How to solve unk_xxxx in IDA View?

I have built an executable file (the architecture is ARMv7, the base SDK is iOS), which depended on an xxx.a file in xcode; I don't have the source code of thexxx.a. I want to check some logic in `xx. ...
1 vote
1 answer
223 views

Log input data and resulting hash for CC_MD5 calls in an iOS app with Frida

I am trying to understand the usage of calls to CC_MD5 in an iOS application. From Apple's man page I can see that when it is called it requires 3 arguments: extern unsigned char * CC_MD5(const void *...
2 votes
1 answer
614 views

Ghidra : iOS Application : Mach-O binary -> Symbol files of dylib or framework are not generated

I'm performing my first reverse on a Mach-O file binary through Ghidra. My problem is that Ghidra doesn't create symbol files of the dylib/frameworks that are loaded in the project. It is really ...
2 votes
0 answers
48 views

Attempting to understand non-XZ file signatures within PBZX chunks

After my previous question from nearly a year ago directing me to the YAA format to make sense of the chunks that could be decompressed, this time we're dealing with the chunks that made pbzx tell us ...
2 votes
0 answers
76 views

How to find how a hash in generated in an iOS app

I'm currently working on an iOS app to replicate a signature which looks to be generated with a MD5 hash. I'm currently using Frida, but haven't had any luck replicating it. I've used the script to ...
2 votes
1 answer
1k views

Setting Breakpoints at functions decoded by Hopper/IDA Pro in an iOS app

So, its been very interesting to reverse engineer an iOS application and I have made significant improvement into learning how to read disassembly and understand them. Now I was trying to debug the ...
1 vote
1 answer
113 views

Radare2 - "/c pointer; offset" command not giving expected response to search instances of the same pair of similar instructions

I am trying to find an offset IOSURFACEROOTUSERCLIENT_VTAB from an iOS kext(IOSurface) using radare2 and there is a need to use the command "/c pointer; offset" as per the instructions in ...
0 votes
0 answers
63 views

How can i make more space for a bigger string in Hopper disassembler?

i made an ios app which simply change the background color when i tap the button. the goal is to change the color with hopper. I successfully changed the color from blue to red but i cannot change ...
0 votes
0 answers
33 views

Is it possible to somehow derive the decryption key for iOS app binaries?

While disassembling an IPA downloaded directly from the App Store CDN, I noticed that the binary had an unusually large entropy. Looking this occurrence up confirmed my suspicion that it was encrypted,...
0 votes
1 answer
59 views

Dumping available XPC interface and methods

I'm reading this article, and it says: The following functions are exposed over XPC to the caller: @protocol _TtP4main21ForkLiftHelperProtcol_ - (void)changePermissions:(NSString *)arg1 permissions:(...
2 votes
1 answer
166 views

Mysterious ARM instruction evaluating result to be 0xfe instead of 0xff

I'm facing some issues while debugging an iOS application for educational purposes. This is an iOS application found on the App Store and has some anti-debugging capabilities built in it. Pretext: ...
1 vote
0 answers
65 views

finding specific string in ios dyld_shared_cache

Im trying to find the library inside a dyld cache that contains a specific string. I grepped the cache file and for the offset of the string, however when im throwing the cache file to ida non of the ...
11 votes
1 answer
4k views

Generating Snapchat Snaptags ("QR" Codes)

For those that haven't seen, Snapchat now has a special type of image based code that allows you to quickly add friends by pointing the camera at the screen, similar to a QR code, called "Snaptags". ...
1 vote
0 answers
44 views

Theos Tweak compilation errors [closed]

While attempting to build a Theos tweak, even a templated one created by Theos, I will encounter the following error bash: line 1: 4665 Done swift --version 4667 Broken pipe:...
11 votes
2 answers
19k views

Decrypting IPA Binary on OS X

I've been reading this PDF on reverse-engineering iOS applications and have reached slide 39, decrypting the binary. However, I've been attempting to disassemble and explore the binary in OS X 10.9.5 ...
4 votes
3 answers
7k views

Can not continue debugging after SIGTRAP

I am trying to debug an iOS app with gdb and when I hit a breakpoint I get this error, and can not continue. Program received signal SIGTRAP, Trace/breakpoint trap. [Switching to process 190 thread ...
1 vote
1 answer
151 views

IDA - ObjC - Meaning of _BYTE and dword_0?

This is my first experience disassembling/reverse engineering, and am having a bit of difficulty keeping up. For reference, I'm trying to uncover the inner workings of a pretty good library in my ...
1 vote
1 answer
65 views

Mach-O ARM64 using literal values instead of a frame pointer (BP) register

I'm investigating an iOS app Mach-O binary in IDA and noticed it's using a fixed constant as an offset to the SP to denote the start of the stack frame instead of a register. Is this normal? ARM ...
6 votes
1 answer
515 views

How does IPA decryption works?

All IPAs being downloaded from AppStore gets encrypted on servers as part of FairPlay DRM. But decryption is accomplished on local device. As far as I know there is some hardware module which contains ...
3 votes
0 answers
579 views

Is there an existing tool to reverse engineer Xamarin AOTDATA files?

I am currently examining a xamarin application. It has used the "ahead of time compilation" feature, which has left some of the associated .net assemblies (.dlls) as lists of function signatures ...
1 vote
1 answer
617 views

How to identify which iOS kernelcache is installed?

I've an iPhone7 running iOS11.3 (15E216). The ipsw for this build version contains two separate kernelcache files named kernelcache.release.iphone9 and kernelcache.release.iphone10. Neither file is an ...
3 votes
1 answer
2k views

Lipo alternate for linux

Currently, I'm using lipo tool to extract the arch type from a fat iOS binary on a Mac OS. Now, I want to do the same on the linux platform for the iOS binaries, i.e. extract a given arch type from a ...
9 votes
2 answers
7k views

How difficult is to decompile C++ file?

I am writing an Android app with AES encryption and I am going to save AES key as a string to a C++ file with extension .cpp. I am also going to create an iOS app which will use the same AES key. Is ...
3 votes
1 answer
2k views

How does Apple enforce the expiration of beta apps distributed through TestFlight

A beta app expired after a period of time. But after some investigated on the ipa file, both the certificate and the mobile provisioning profile embedded in the bundle are not expired. How can Apple ...
42 votes
1 answer
92k views

Decompiling iPhone App

I've been searching this site and more, but I haven't had much luck. I want to decompile an app to see how part of it works, and I've tried multiple programs. I've tried Hopper, IDA, and some other ...
0 votes
1 answer
143 views

Accidently removed cordova platform ios folder [duplicate]

I was trying to uninstall a plugin but accidently ran the command cordova platform remove ios and it removed the app code on my macbook. I don't see anything in trash as well. Is there any way to ...
0 votes
1 answer
236 views

Newbie here: hidden values in assembly? [closed]

So i'm new to the whole reverse engineering thing with only experience in C#. So I wanted to try and change the framerate of applications (eg. this unity game) at an assembly level on iOS ( I have an ...