[ILSpy plugin for Visual Studio Code](https://github.com/icsharpcode/ilspy-vscode): You can have it in any OS \(you can install it directly from VSCode, no need to download the git. Click on **Extensions** and **search ILSpy**\).
If you need to **decompile**, **modify** and **recompile** again you can use: [**https://github.com/0xd4d/dnSpy/releases**](https://github.com/0xd4d/dnSpy/releases) \(**Right Click -> Modify Method** to change something inside a function\).
You cloud also try [https://www.jetbrains.com/es-es/decompiler/](https://www.jetbrains.com/es-es/decompiler/)
This is necessary because if you don't do this, at **runtime** several **optimisations** will be applied to the code and it could be possible that while debugging a **break-point is never hit** or some **variables don't exist**.
Then, if your .Net application is being **run** by **IIS** you can **restart** it with:
```text
iisreset /noforce
```
Then, in order to start debugging you should close all the opened files and inside the **Debug Tab** select **Attach to Process...**:
Now that we are debugging the process, it's time to stop it and load all the modules. First click on _Debug >> Break All_ and then click on _**Debug >> Windows >> Modules**_:
Then, when you start debugging **the execution will be stopped when each DLL is loaded**, then, when rundll32 load your DLL the execution will be stopped.
But, how can you get to the code of the DLL that was lodaded? Using this method, I don't know how.
### Using x64dbg/x32dbg
* **Load rundll32** \(64bits in C:\Windows\System32\rundll32.exe and 32 bits in C:\Windows\SysWOW64\rundll32.exe\)
* **Change the Command Line** \( _File --> Change Command Line_ \) and set the path of the dll and the function that you want to call, for example: "C:\Windows\SysWOW64\rundll32.exe" "Z:\shared\Cybercamp\rev2\\14.ridii\_2.dll",DLLMain
* Change _Options --> Settings_ and select "**DLL Entry**".
* Then **start the execution**, the debugger will stop at each dll main, at some point you will **stop in the dll Entry of your dll**. From there, just search for the points where you want to put a breakpoint.
Notice that when the execution is stopped by any reason in win64dbg you can see **in which code you are** looking in the **top of the win64dbg window**:
[**Blobrunner**](https://github.com/OALabs/BlobRunner) will **allocate** the **shellcode** inside a space of memory, will **indicate** you the **memory address** were the shellcode was allocated and will **stop** the execution.
Then, you need to **attach a debugger** \(Ida or x64dbg\) to the process and put a **breakpoint the indicated memory address** and **resume** the execution. This way you will be debugging the shellcode.
You can find a slightly modified version of Blobrunner in the following link. In order to compile it just **create a C/C++ project in Visual Studio Code, copy and paste the code and build it**.
\*\*\*\*[**jmp2it** ](https://github.com/adamkramer/jmp2it/releases/tag/v1.4)is very similar to blobrunner. It will **allocate** the **shellcode** inside a space of memory, and start an **eternal loop**. You then need to **attach the debugger** to the process, **play start wait 2-5 secs and press stop** and you will find yourself inside the **eternal loop**. Jump to the next instruction of the eternal loop as it will be a call to the shellcode, and finally you will find yourself executing the shellcode.
You can download a compiled version of [jmp2it inside the releases page](https://github.com/adamkramer/jmp2it/releases/).
### Debugging shellcode using Cutter
\*\*\*\*[**Cutter**](https://github.com/rizinorg/cutter/releases/tag/v1.12.0) is the GUI of radare. Using cutter you can emulate the shellcode and inspect it dynamically.
Note that Cutter allows you to "Open File" and "Open Shellcode". In my case when I opened the shellcode as a file it decompiled it correctly, but when I opened it as a shellcode it didn't:
In order to start the emulation in the place you want to, set a bp there and apparently cutter will automatically start the emulation from there:
You can see the stack for example inside a hex dump:
scDbg also counts with a graphical launcher where you can select the options you want and execute the shellcode
The **Create Dump** option will dump the final shellcode if any change is done to the shellcode dynamically in memory \(useful to download the decoded shellcode\). The **start offset** can be useful to start the shellcode at a specific offset. The **Debug Shell** option is useful to debug the shellcode using the scDbg terminal \(however I find any of the options explained before better for this matter as you will be able to use Ida or x64dbg\).
### Disassembling using CyberChef
Upload you shellcode file as input and use the following receipt to decompile it: [https://gchq.github.io/CyberChef/\#recipe=To\_Hex\('Space',0\)Disassemble\_x86\('32','Full%20x86%20architecture',16,0,true,true\)](https://gchq.github.io/CyberChef/#recipe=To_Hex%28'Space',0%29Disassemble_x86%28'32','Full%20x86%20architecture',16,0,true,true%29)
This ofuscator change all the instructions for `mov`\(yeah, really cool\). It also uses interruptions to change executions flows. For more information about how does it works:
If you are lucky [demovfuscator ](https://github.com/kirschju/demovfuscator)will deofuscate the binary. It has several dependencies
```text
apt-get install libcapstone-dev
apt-get install libz3-dev
```
And [install keystone](https://github.com/keystone-engine/keystone/blob/master/docs/COMPILE-NIX.md) \(`apt-get install cmake; mkdir build; cd build; ../make-share.sh; make install`\)
If you are playing a **CTF, this workaround to find the flag** could be very useful: [https://dustri.org/b/defeating-the-recons-movfuscator-crackme.html](https://dustri.org/b/defeating-the-recons-movfuscator-crackme.html)
