Deobfuscation can also be used as an investigative technique to help find vulnerabilities in software. For example, a deobfuscator can help you understand what an attacker might have done to exploit your application.
Deobfuscators are often used to unpack, clean, and rewrite source code, freeing up intermediate and late-stage compilation. Today, many developers use it to investigate, reverse-engineer code, or analyze other developers' code.
How Does DeObfuscation Work?
Some of this obfuscation is caused by "minification," which is the act of decreasing the total byte count of your source as much as feasible for space reasons. This entails reducing variables to one character IDs and converting phrases such as true to something shorter but comparable like "!0".
What Are the Benefits of Deobfuscation?
A deobfuscator is an important tool for software developers. It takes obfuscated code, breaks the code down into its components, and then makes it easy to understand again. This way, you can figure out exactly what your code is doing and how it’s performing.
Additionally, a deobfuscator helps you keep your applications secure by finding security vulnerabilities that you may have missed while developing your application. Security vulnerabilities like XSS (cross-site scripting) and SQL injection are often overlooked during development because they’re difficult to detect without a deobfuscator's help.
With a deobfuscator, you can also easily reverse-engineer the code of other developers. That’s because the developer won’t be able to use any obfuscation tricks or shortcuts to hide their work from you. They'll be forced to write clear and readable code that can be easily understood by anyone who’s looking at it.
Js Deobfuscation Steps
The initial step is to obtain the isolated source for examination.
The second step in deobfuscation is identifying the type of obfuscation used and creating the appropriate preprocessors and post-processors.
The next step is to run a series of deobfuscation methods in a loop until they are no longer effective. Once that happens, it's time to apply post-processors to the now deobfuscated code.
Finally, the code is normalized to remove any dead code. When dealing with code, it is important to know whether a method is using eval to resolve its output or not. Using eval is considered unsafe even when running it in a sandbox environment like vm2.