Complete guide to Deobfuscating Javascript

Today everyone wants to protect his work by any means and to protect JavaScript codes most developers obfuscate the code or encode the code which makes it harder for other developers to understand the code and reuse it.

Most of the developers search for this issue and they don't find any medium to decode or deobfuscate JavaScript code.

What is obfuscation?

Obfuscation is source code modification as a result it becomes difficult to read and understand, but its functionality does not change. Obfuscation is used for source code in interpreted (rather than compiled) programming languages.

Obfuscation is especially relevant for JavaScript, because, unlike, for example, PHP which runs on the web server, JavaScript is loaded into the browser and everyone can have access to scripts.

Obfuscation uses different tricks. One of them is the removal of spaces. This is called code minify and is used not only to obfuscate but to speed up script downloads. As a side effect, this code is really hard to figure out.

Often during obfuscation, the code turns into a meaningless set of functions and lines that cannot be understood, but ultimately do exactly the same thing as the source code. But there are really amazing examples of obfuscation, for example, JSFuck can display any JavaScript code with just the following six characters []()!+

For example, the following code is workable JavaScript code:

[][(![]+[])[+[]]+([![]]+[][[]])[+!+[]+[+[]]]+(![]+[])[!+[]+!+[]]+(!![]+[])[+[
]]+(!![]+[])[!+[]+!+[]+!+[]]+(!![]+[])[+!+[]]][([][(![]+[])[+[]]+([![]]+[][[]
])[+!+[]+[+[]]]+(![]+[])[!+[]+!+[]]+(!![]+[])[+[]]+(!![]+[])[!+[]+!+[]+!+[]]+
(!![]+[])[+!+[]]]+[])[!+[]+!+[]+!+[]]+(!![]+[][(![]+[])[+[]]+([![]]+[][[]])[+
!+[]+[+[]]]+(![]+[])[!+[]+!+[]]+(!![]+[])[+[]]+(!![]+[])[!+[]+!+[]+!+[]]+(!![
]+[])[+!+[]]])[+!+[]+[+[]]]+([][[]]+[])[+!+[]]+(![]+[])[!+[]+!+[]+!+[]]+(!![]
+[])[+[]]+(!![]+[])[+!+[]]+([][[]]+[])[+[]]+([][(![]+[])[+[]]+([![]]+[][[]])[
+!+[]+[+[]]]+(![]+[])[!+[]+!+[]]+(!![]+[])[+[]]+(!![]+[])[!+[]+!+[]+!+[]]+(!!
[]+[])[+!+[]]]+[])[!+[]+!+[]+!+[]]+(!![]+[])[+[]]+(!![]+[][(![]+[])[+[]]+([![
]]+[][[]])[+!+[]+[+[]]]+(![]+[])[!+[]+!+[]]+(!![]+[])[+[]]+(!![]+[])[!+[]+!+[
]+!+[]]+(!![]+[])[+!+[]]])[+!+[]+[+[]]]+(!![]+[])[+!+[]]]((![]+[])[+!+[]]+(![
]+[])[!+[]+!+[]]+(!![]+[])[!+[]+!+[]+!+[]]+(!![]+[])[+!+[]]+(!![]+[])[+[]]+(!
[]+[][(![]+[])[+[]]+([![]]+[][[]])[+!+[]+[+[]]]+(![]+[])[!+[]+!+[]]+(!![]+[])
[+[]]+(!![]+[])[!+[]+!+[]+!+[]]+(!![]+[])[+!+[]]])[!+[]+!+[]+[+[]]]+[+!+[]]+(
!![]+[][(![]+[])[+[]]+([![]]+[][[]])[+!+[]+[+[]]]+(![]+[])[!+[]+!+[]]+(!![]+[
])[+[]]+(!![]+[])[!+[]+!+[]+!+[]]+(!![]+[])[+!+[]]])[!+[]+!+[]+[+[]]])()

Obfuscation is used by both legitimate users who want to protect their ideas and their code from theft, and hackers to make it difficult to analyze their methods and programs.

What is deobfuscation?

Deobfuscation is the reverse process of obfuscation, that is, the translation of code from a hard-to-read form into an understandable one or reverting it to its original form.

Since there are many obfuscation methods, deobfuscation methods, and tools are also many and they have different abilities and varying degrees of effectiveness.

Deobfuscation is needed both in the analysis of malicious code and in the study of the target site to understand the logic of its operation and search for vulnerabilities.

How to deobfuscate javascript code?

There are many tools available on the internet today to deobfuscate javascript code and you can use that tools free of cost, I mean that tools these days are totally free but I am not sure about the future :)

JavaScript Deobfuscation Tools

There are many online tools or websites available online to decode javascript codes online but the best of all in my opinion is de4js online javascript deobfuscator online tools the best, you can visit the site by clicking the button below.

Here is a list of some popular JavaScript deobfuscation tools:

• JSFuck Decoder
• UnPacker
• Deobfuscator
• JSDetox
• JSDebugger
• Beautifier
• JSNice
• Jscrambler
• JSOptimizer
• JavaScript Deobfuscator Extension for Chrome DevTools.

These tools are designed to help reverse the process of obfuscation and make the code more readable, but the results can still be difficult for a human to interpret without significant effort.

Javascript Deobfuscator Online Tool

Unable to Decode your Code?

If you are not able to decode your code you can hire me on Fiverr to do it for you.

Hire Me

Bonus Points:

Here are some bonus techniques for deobfuscating JavaScript code

Code Beautification: The first step in deobfuscating JavaScript is to format the code into a more readable format, using tools like JavaScript Beautifier or Pretty Print.

String Decryption: Many obfuscators encrypt strings within the code, so they can be decrypted and the original strings can be extracted.

Debugging: Debugging the obfuscated code using tools like Chrome DevTools or Firebug can reveal hidden functionality and show the values of variables at runtime.

Function Naming: Obfuscated code often uses meaningless or short function names, so renaming these functions to descriptive names can make the code much more readable.

Code Flow Analysis: Analyzing the control flow of the code can help to understand how the code works and can reveal the logic behind obfuscated code blocks.

Reversing the Obfuscation Algorithm: By understanding how the obfuscation was performed, it may be possible to reverse the algorithm and produce the original, unobfuscated code.

Deobfuscating JavaScript code can be a complex and time-consuming process, so it is important to have a strong understanding of JavaScript and how it works.