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Questions tagged [decompilation]

Process of translating assembly code extracted from a binary file in a structured programming language, such as C.

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Is it possible to recover the key to a decrypted file?

Is it possible to recover the key to a decrypted file if you have the initialization vector and it uses RijndaelManaged? If so how? The file I want to recover the key from is a xml that looks like ...
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1answer
81 views

Can I define custom enum-type to be used in Ghidra as a data type?

I'm trying to learn Ghidra. Say, if it generated the following code for loading functions from an array of function names from gpfnCommCtrlAPI: I was able to retype gpfnCommCtrlAPI into char*[14] ...
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1answer
43 views

De-obfuscating code ran through JScrambler 3x via Eval() functions

I am relatively new to JS and de-obfuscation in general and I am having difficulties reversing some complicated JS. I know the code itself is obsfucated via jscrambler 3-4x and therefore is ran ...
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35 views

deobfuscating/decompiling extremely complicated javascript [on hold]

I am working with some extremely complicated JavaScript. It is around 70,000 lines long and sections of the code look like this U2xx.l11="0x78920d50";m2xx.r9G="11";b2xx.v3y="0x744ebc37";P2xx.K5h="...
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1answer
109 views

Unable to decompile C Code

Recently, i have gone through some kind of win32-64 executable files which can't be decompiled under IDA (into Pseudocode). Only the Assembly Code can be read. When i try to press F5 to decompile the ...
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154 views

How to load symbols from a symbol server in Ghidra?

I've been trying to learn Ghidra by attempting to reverse the comctl32.dll system library, which has many of its functions documented. I started the de-compilation analysis in it, and after a while it ...
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1answer
93 views

Decryption loops

I'm reversing a CTF binary and I found a decryption loop decompiled by IDA like this: for ( i = 0; i < n; ++i ) { v22 = *((_BYTE *)sub_5657D89B + i); v0 = v22 ^ 0x90; v1 = strlen(&...
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102 views

How can I convert the following assembly code to pseudo code?

I got the following disassembly code in IDA pro. I really find it hard to convert it into pseudo code. push ebp mov ebp, esp sub esp, 14h mov dword ptr [ebp-14h], 1 mov dword ptr [ebp-10h], 2 mov ...
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25 views

Is there any way to execute Hopper scripts from command line?

What should I do if I have a batch of binaries to decompile with Hopper? I know how to run a Hopper script in the UI interface, is there any way to run Hopper scripts from command line? Or any other ...
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1answer
101 views

Is there any decompiler, which can produce a compilable result?

I would like to decompile a 32bit linux executable to C, modify some parts of it, and then compile it back. I do not care if the C code is not pretty and really hard to maintain. The only thing I care ...
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54 views

How to decompile these LUAs from the Bookworm Adventures games?

I'm trying to decompile the LUCs (customly extensioned LUAs) from both of the games but they won't decompile, they aren't encrypted and use LUA version 5.0.2 (32-bit) according to the game's code. ...
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41 views

Taking a luac file and making a modification

I have a luac file for a program I use. I'd like to make a modification to this file to call a function from another luac script. My understanding of the way luac works is the first few bytes are the ...
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1answer
48 views

Calculate LEA operand

I have those opcodes on 64 bits: 48 8D 35 45 CE FF FF >>> lea rsi, [rip - 0x31bb]. How can I get the 0x31bb value from those opcodes and how can I know if I have a + sign or a - sign ...
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1answer
313 views

Impossible to execute a program with radare2 : TO DO continue

I am trying to crack a crackme. I already catch the flag because I seen the string variable which represants flag. I would like to catch the flag on an other way, I want to set a breakpoint when there ...
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0answers
109 views

Reconstruct InnoSetup file with existing CompiledCode.bin

Is it possible to somehow re-compile/reconstruct Inno Setup file and use existing CompiledCode.bin ? I dont have the source of CompiledCode.bin and writing from scratch is not an option. Basically ...
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207 views

How can I make IDA understand this switch statement with a signed jump table?

I took the following C code and compiled it on Ubuntu 16.04 with GCC 5.4.0: int main() { int a = 0; for (int i = 0; i < 5; i++) { switch (i) { case 0: a = 1; break; ...
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1answer
265 views

Reverse Engineering bios of ATM Machine

I bought an Hyosung NH1500 off Offer-up and it boots up and initializes some peripherals and then spits out and error of "COM download is failed". I've searched Google and 0 results came up, I've been ...
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28 views

How to tell when Cor20 starts for DLL's that are supposed to meet ECMA-335?

When I look at a .Net compiled DLL that is supposed to conform to ECMA-335, I see the PE Header well defined up to 0x1EF, but there seems to be block between 0x1F0 and 0x208 which is mainly 00's that ...
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102 views

IDA 7 handling strings in debugger pseudocode

When running a remote debugger to a linux server, is there a way to get IDA (7.0) to properly handle strings? When I go to the pseudocode view, I get things like this; v7 = sub_804AD60((std::string *)...
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1answer
109 views

Multiple decompilation failure with ntoskrnl

IDA v7 shows decompilation failure in 64bit ntoskrnl.exe file of Windows 10 build 18262. Here is an example of that: I've loaded all the needed type libraries, PDB file, kernel mode header files (wdm....
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1answer
419 views

XCHG RAX, RAX: 0x09, what does this code do and how does it work?

Given the following short assembly snippet: shr rax, 3 adc rax, 0 I worked this out a bit: We know SHR sets the CF with the last bit shifted. We know ADC dest, 0 is just adding the CF. So ...
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1answer
303 views

Converting Assembly x64 code to C

I have the following code: 0000000000400526 <main>: 400526: 55 push rbp 400527: 48 89 e5 mov rbp,rsp 40052a: 48 83 ec 20 sub ...
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1answer
117 views

Figuring out what a segment of assembly code does

I have the following assembly code: 0000000000400711 <foo>: 400711: 55 push rbp 400712: 48 89 e5 mov rbp,rsp 400715: 48 89 7d e8 ...
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95 views

Need help understanding IDA Pro pseudocode

I am new into IDA and have some questions about the pseudocode in C. Could someone please explain to me the meaning of the following two lines: (*(void (__fastcall **)(int *, _DWORD))(*v1 + 196))(v1, ...
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796 views

What does this assembly language program output?

I have been struggling with this for a long time. I have the following assembly language code: .intel_syntax noprefix .bits 32 .global asm0 asm0: push ebp mov ebp,esp mov eax,DWORD ...
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1answer
216 views

Need help identifying main processor for Roland synthesizer

I desperately need help figuring out the ic chips in this unit so I can view the firmware in ida pro. So the unit is a roland gr-55 guitar synthesizer and i'm trying to disassemble the firmware into ...
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1answer
219 views

What is the password to this file? I can't figure it out with radare2 or gdb

Here is the binary file. https://drive.google.com/file/d/1ywN60yZYIhPPRyZMGbQudZRYoLYBhkeJ/view?usp=sharing I am able to figure out some of the assembly, but can't get the correct password. I know ...
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1answer
918 views

How do the AI in Pokemon battles work?

Has anyone ever attempted to decompile the code for a Pokemon game and figure out how the battle AI works? e.g. How it decides which move to use, or use a Potion/even withdraw based on the current ...
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3answers
118 views

How to identify the purpose behind a bitmask?

The bitmask is used to manipulate the value of the integer variable. From debugging, I guessed that the bitwise operation generates nearest even integer. Here is the assembly: mov r8d, 0FFFFFFF8h ...
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1answer
50 views

Do all class instances have a relative address/offset and can i make a copy of any class pointer?

I'm familiar with finding a player base pointer as-well as other values in games, and finding offsets and such. And I have applied that to some of my own code in the past. But does this practice ...
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106 views

Change value of an IF condition found in IDA

so I have the .idb file of an executeable I want to modify. In the IDB file, I found this code And I basically want to change 4111006 to 1006 in that IF condition. however, when I press TAB to go to ...
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301 views

Generate c like pseudo code from objdump output

Ida has a feature which generates pseudo code from assembly. Is there a tool under Linux that make the same job, from objdump output for example ?
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0answers
106 views

Show parameters stored in stack with __fastcall in IDA

This is an extension of my previous question. Here is a sample of assembly in x64 Windows executable using COM virtual function with __fastcall convention. mov [rsp+32], rdx ...
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1answer
164 views

Android 7.0+ Monitoring application HTTPS requests

I am trying to capture https requests an application performs during runtime without any success yet. Different failing approaches, using mitmproxy / charles proxy and user ca certificates, obtaining ...
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1answer
304 views

How to find the executable code of the native method in the library * .so? (Android)

I'm doing reverse engineering of a mobile application for android and I had a question how to find the executable code of the native method in the library * .so. From the code of the code, the native ...
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1answer
282 views

Resolving FLAGS bits with IDA

While disassembling a binary, IDA decompiler decompiles the call as mmap(0x80000000, 4096, 7, 50, -1, 0); While there is nothing wrong with the decompilation itself, it could be more useful to decode ...
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163 views

Translating ida macros and pseudocode into C++/C

What would be the translated C output of this hexrays decompiler pseudocode? The values of v6 and v5 are floats just as v8. The value of xmmword_108365D0 is 7FFFFFFF7FFFFFFF7FFFFFFF7FFFFFFFh v8 = (...
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1answer
477 views

How to unpack Inno Setup bundles with Arc+SREP data?

I've stumbled upon Inno Setup installer with additional separate Arc archives (commonly with .bin extension) that I was unable to extract using normal methods: the installer didn't work for an ...
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0answers
81 views

Hopper: What does stack[xxxx] mean?

When using the 'decompiler' tool in Hopper on the start function of an application it shows this: What does the stack[2043] mean, is it 2043 bytes from the top of high memory and its assigning it to ...
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2answers
1k views

IDA Hex-Rays Decompiler : Show strings instead of offset

How can i settings IDA show me string instead of offset_xxx?
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1answer
175 views

Help understand decompiled IDA code

I got stuck at yellow lines, dont understand what it's gonna do. Need advice or help, thanks! File : https://www.sendspace.com/file/3yowjg Password : 1 void __fastcall sub_A513C0(char *Src, HWND ...
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0answers
398 views

Decompiling or modifying .exe file generated from .jar

I have one .exe file which is generated from .jar file but I'm not sure how it was made. I cannot open it with winrar or something. I need to modify it or just to decompile it. Any answer should be ...
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1answer
300 views

IDA: NEC V850. Unable to identify anything

I'm trying to reverse a V850E binary (it was extracted from an official update), however, IDA doesn't recognize anything at all. In order to do that, I select a V850 or V850E1 processor type and ...
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0answers
49 views

Decompiling DotNet2JScript malware?

I've got a .NET malware sample that was transpiled to JScript using DotNet2JScript. The .NET malware assembly was serialized to binary form using BinaryFormatter and then embedded into the JScript ...
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1answer
174 views

What are the steps to reverse engineering a Shockwave .DCR file?

I have been fascinated by reverse engineering after making several emulators and finding the pret community. I love the idea behind decompiling old games and recreating source code that recompiles ...
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1answer
288 views

Would it be possible to reverse engineer a game's rom file to get source code?

More specifically, could you get low level code from a rom, and piece it together and translate it to a higher level language?
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1answer
1k views

dnSpy - What do these symbols mean?

When decompiling a dll file there are certain lines of code that read like this: return \u0013.\u0002.\u0001(url, info); I have two questions on this: 1) does \u00xx mean that it is obfuscated, if ...
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0answers
93 views

Reverse engineering IE thick client

Internet Explorer allows for creating thick clients that run in the browser via a Browser Helper Object (BHO). In trying to reverse one such thick client I noticed that the website downloads about ...
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1answer
136 views

Disassemble/decompile arbitrary JVM bytecode

I have an obfuscated java binary which does runtime code injection using java reflection like this. Object o = "a long string"; ((Method)o).invoke(params..); (If I write this in a java file, it ...
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1answer
154 views

Fixing IDA Member functions argument order

When IDA realizes a function relies on the this* pointer it often places as the second variable. Severely mucking up things. I was wondering is there away to fix this and maybe in turn help type ...