12 Best Free EXE Decompilers, Debuggers & Windows disassembler (Online & Offline)

by error4hack · July 21, 2019

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This post lists some of the best exe decompilers and Windows disassembler. Lets first know the basic difference between the disassemblers, decompilers, and debuggers. So without any further ado lets gets started.

Table of Contents

What is the difference between Disassembler, Decompiler, and Debuggers?

Disassemblers:
- Disassemblers are the complete opposite of Assemblers i.e they let you reverse binaries into assembly code. For eg: W32DASM
Decompilers:
- Decompilers let you reverse binaries into higher-level languages like C, C++, Visual Basic. For eg: VB Decompiler
Debuggers:
- They let you view & change the state of the program while it is running. For eg: Ollydbg, Windbg

Reference: https://danielmiessler.com/blog/the-difference-between-decompilers-disassemblers-debuggers-and-hex-editors/

Ollydbg

Olly Debugger is one of the most used Ring 3 debuggers for 32bit programs for Microsoft® Windows®. It is a dynamic debugger that enables the user to change the source code while the program is running. Ollydbg was created by Oleh Yuschuk & its last stable release was in 2013, so it is quite old & it does not run effectively on 64-bit machines.

Pros:

Shareware but FREE to use.
Very Powerful dynamic debugger.
Easy to use for beginners.
Allows you to load and debug DLLs directly.
A lot of Plugins & Scripts available.

Cons:

Works for Microsoft® Windows® only.
Meant only for 32-bit software.
It is not generally used for static debugging.

X64dbg

It is open-source debugger for executable files developed by Mr. eXodia for both x86 & x64 processor types. x64dgb is a brand new debugger in the sector. It is a more likely 64-bit version of ollydbg and is a dynamic type debugger.

Pros:

Fully free & open source.
Supports both 32 & 64-bit files.
User-friendly interface.

Cons:

Only meant for windows.
A quite nascent tool as compared to others.

ALSO READ-: Click to view Beginner-friendly x64dbg Reverse Engineering tutorial.

VB Decompiler

It is the exe decompiler for Visual Basic applications & disassembler for Visual Studio .NET apps. VB Decompiler can recover the lost source code of your Visual Basic applications. It supports disassembling and analyzing the IL code of Visual Basic .NET, C#, etc. You can download VB Decompiler’s free LITE version & its plugins by clicking here.

Pros:

It supports Visual Basic and .NET applications.
Supports both 32 & 64-bit files.
User-friendly interface.

Cons:

Its fully featured version is not free of cost, in fact pretty expensive.

Java Decompiler Online

As the name suggests “Java Decompiler Online” is an online Java Decompiler. You can use Java Decompiler Online by clicking here.

Pros:

Completely free of cost.
It also supports the apk file and its resources decompilation.

Cons:

It is not as feature-rich as other offline java decompilers in the market.

Bonus: If you want to decompile apk files online, you can do so by clicking here.

Online DisAssembler(ODA)

“Online Disassembler” is an online disassembler which supports EXE, ELF, PE, COFF, and other executable file formats. You can use Online Disassembler for free by clicking here. To use this online service simply Upload the file & use the disassembler as per your wish.

Pros:

It is completely free of cost.
Very feature-rich.

Cons:

Does not support dotNET files.

Immunity Debugger

Immunity Debugger is a popular alternative of Ollydbg & Windbg. It has a command-line as well as GUI based User Interface. It also supports Python scripting, hooks & graphs.

IDA Free

This may sound hilarious, but yes if you are a beginner and can’t afford to use IDA Pro then you can use IDA Free version which can be downloaded here. It is best for beginners who are starting their journey to get the feel of using sophisticated debugger. Although IDA Free has some serious limitations over IDA Pro, it is still worth a shot. If you want to use IDA with full features you can either use IDA Pro or GHIDRA for free.

Pros:

Completely free of cost

Cons:

Debugging not allowed
IDAPython feature not present
No commercial usage allowed
Lacks many popular processors
No technical support

dotPeek

DotPeek is a Free .NET Decompiler developed by JetBrains. It can decompile .NET assemblies to C# or Intermediate Language(IL). dotPeek supports exe, dll & winmd(metadata files). It lets you view IL code as comments to decompiled C#, or you view IL code in a separate window. You can use dotPeek for free by clicking here.

Pros:

Completely free of cost.
Very feature-rich.

Cons:

Not meant for native executable files.

Windbg

Windbg (also known as Windows Debugger) is Microsoft’s kernel-mode debugger for Windows. It is a Kernel Mode i.e. Ring 0 debugger that can be used to debug user-mode programs or device drivers. It is cost-free compared to IDA Pro which is very expensive. But, particularly for beginners, it’s not very user-friendly.

Pros:

Completely Free
Powerful Kernel level debugger

Cons:

Not very user-friendly interface especially for newbies
It only supports the Windows platform
It is not a Ring 3 debugger so you cannot debug normal apps with it.

GHIDRA

Ghidra is one of the excellent alternatives to Ollydbg debugger. It is COMPLETELY FREE of cost and open-source tool developed by the NSA. Ghidra is a very powerful exe decompiler and debugger written in Java and C++. It supports the following key architectures-:

32(x86) and 64 bit
ARM and AARCH64
MIPS
Java
DEX(Android)
8051

You can download Ghidra’s latest version here.

Pros:

Fully free & open source
Supports both 32 & 64-bit files
User-friendly interface

Cons:

Currently very new, compared to competitors

ILSpy

ILSpy is a free .NET decompiler. It relies on Mono.Cecil library to read .NET assemblies. You can download and use ILSpy by clicking here and you can also try its portable version by clicking here.

Pros:

Fully free & open source.
Supports both 32 & 64-bit files.
User-friendly interface.

Cons:

Not much useful when the file is obfuscated.

dnSpy

dnSpy is a moded version of ILSpy by 0xd4d. dnSpy is more powerful and versatile than ILSpy. It is free of cost & relies on Mono.Cecil library to read .NET assemblies. You can download and use dnspy by clicking here and make sure to read the instructions given there if it doesn’t run on your machine.

Pros: