11 votes
Accepted

How do I reverse this javascript code? How is it packed?

1. The script writes a <script src=...> tag at the end, so to know what it is doing, you could change the last document.write to a console.log or other defanging measures to see that this is ...
  • 446
9 votes
Accepted

How to deobfuscated javascript?

UPDATE Based on @ws's comment and @nderscore's code, use this JSFiddle to decode the thing. To find the password that this script asks for, you can use a simple debugging trick. Go to JSFuck and ...
  • 1,283
8 votes
Accepted

How work this obfuscation, and how deobfuscate?

This obfuscated code is taking advantage of the wide possibilities to name Javascript variables. This makes a simple-obfuscated Javascript code to look much more scarier. As noted in the great ...
  • 8,809
6 votes

What is a good tools to reverse the effects of Minify on JavaScript?

I recently tried http://www.jsnice.org/ on 50+KB of a single minified JavaScript file containing lots of dynamic modification code that Cordova's runtime refused to execute (for an app targeted at ...
6 votes
Accepted

How can I deobfuscate this javascript code

The special "accent" letters are just a distraction. You can use a text-editor to replace them with "standard" letters and the code would still work. Let's add a newline after each semicolon: É=-~-~[...
  • 529
5 votes
Accepted

Obfuscated code analysis - can unused variables be ignored?

This might be true that those variables are added only to confuse analysis but remember that in Javascript there are so many ways to access the variable that I would take such info from an automated ...
5 votes

How work this obfuscation, and how deobfuscate?

It just uses very difficult to read variable names and do some JS trickery to confuse you what it does. If you replace those strange characters you'll get a bit of more readable form a=~[]; a={___:++...
5 votes
Accepted

How can I modify or decompile Hermes JS bytecode?

My friend made this tool: hbctool, a Hermes bytecode disassembler/assembler. This will help you disassemble the file into a more readable format (similar to hbcdump), so you can modify and re-assemble ...
  • 66
4 votes

Analyzing highly obfuscated JavaScript

In addition to the other useful links here, I recommend to try Malware-Jail Sandbox for semi-automatic Javascript malware analysis, deobfuscation and payload extraction. Written for Node.js malware-...
  • 183
4 votes

How to get Video URL from embedded Link in Twitter

youtube-dl is a nice program to download media content from a lot of websites, including twitter (and despites program name). It is open source, studying it can help understand how to retrieve the ...
4 votes
Accepted

reverse javascript crackme encryption method algorithm

To extend on EWD-0- about the reversibility of RC4 here's how I tried it: From your actual code and reversing it a little to get "input128" encoded: arr = [99, 116, 115, 37, 16, 120, 211, 90, 197, ...
  • 156
4 votes

How to copy video address from tweet?

I could not quite track how exactly it's done but youtube-dl can do it. Run it with -v or -g to see the final video URL: C:\Work>C:\Python27\Scripts\youtube-dl.exe -v https://twitter.com/starwars/...
  • 35.6k
3 votes
Accepted

How decrypt hexadecimal javascript code?

Those hex values could represent anything. Look for online converters that convert hexadecimal to text (consider various formats), dec, etc. and see if the results make any sense. If not, then they ...
  • 2,194
3 votes
Accepted

Is deobfuscation of my javascript code hard or easy?

Resolved. generally nothing in js is impossible to reverse in this case the 'alert' string in plain text give me a big help, because I simply started to resolve function value one step back at time. ...
  • 183
3 votes

How to get Video URL from embedded Link in Twitter

You were looking at the wrong piece of code. Twitter features lightly obfuscated javscript. Bring it to order and you'll receive something like this: { "duration": 55322, "scribe_widget_origin": true,...
  • 2,886
3 votes

Reverse engineering a java applet using python/Javascript

If I understand well, you would like to reverse a Java applet in order to plug your own tool on a specific API (which is incidentally a trading platform). I do not know why you are speaking about ...
  • 18.5k
3 votes
Accepted

Is it possible to completely reverse this code?

Having such code the first thing to do is to analyze what part is the obfuscation algorithm and what's the actual code. Here' it's not that difficult as all the code is on top. So let's analyze it ...
2 votes

Try to deobfuscate multi layered javascript

You could try using de4js. For the javascript snippet in the original post, de4js produces the following output: var _0x2815 = ["3 1(){2 0=5;4 0}", "|", "split", "x|myFunction|var|function|return|", "...
2 votes

Frida manipulating arguments - Android

If I understand your question correctly, you want to change the parameter, v, inside the inner function. Right? If that's the case, you would already have access to the v argument inside your inner ...
  • 121
2 votes
Accepted

IDA Pro Alternative for JavaScript?

Have a look at https://github.com/scottrogowski/code2flow for generating callgraphs. Turn your Python and Javascript source code into DOT flowcharts Code2flow will sweep through your project ...
  • 7,432
2 votes

How to call an item of a Javascript array?

The variable _0xe984 in your example is an array of strings, therefore, calling it with _0xe984("0xa") is actually to call as if it was a function that gets the string "0xa" as a parameter. Thus, the ...
  • 8,809
2 votes

How do I decode this JavaScript code?

You can use this tool to partial deobfuscate that code: http://jsnice.org/ In that case I get this: 'use strict'; (function(data, i) { /** * @param {number} isLE * @return {undefined} */ ...
2 votes

would be possible to deobfuscate javascript code?

All the strings you see \x41\x42\x43 are nothing but normal chars encoded as hex of their ascii values. You can decode them as follows: >>> "\x41\x42\x43".decode("utf-8") u'ABC' by trying ...
2 votes
Accepted

Is v8's --print-bytecode safe?

--print-bytecode is not safe. echo "process.exit(42)" > test.js node --print-bytecode ./test.js It exists with status_code = 42. So that code is getting executed. It is not safe.
  • 1,694
2 votes
Accepted

Load a *.dylib or *.so object into the Javascript V8 runtime?

I was misinterpreting the context of the comment in the original link, it seems. I was under the impression that Module.load was a v8-ism, while it in fact appears to be a Frida-API. https://frida.re/...
2 votes
Accepted

HTML/JS app - getting a reference to an element which is not part of the DOM

Look for any requests to document.createElement or document.createElementNS in the code that may be creating and appending the <video> element to the DOM. You might be able to locate the <...
1 vote

How do you un-obfuscate JS code that is evaluating your browser environment?

Start from making JS code more readable using some JS beautifier, there are online tools for that too: https://beautifier.io Then start debugging it in some JS IDE, or just in Chrome developer tools ...
  • 1,810
1 vote

Obfuscated code analysis - can unused variables be ignored?

Often then unsued variables are unusued only until you make the first deobfuscation step. After first run, you could see that some code uses these variables, for example using an eval. This because ...
  • 183
1 vote

deobfuscating javascript injected into Wordpress

I rolled this slice of code through debugger and here is the function that is meant to be executed in the end. "moved = 0; besend = false; function get_query() { besend = true; ua = navigator....
  • 304
1 vote

reverse javascript crackme encryption method algorithm

RC4 is a Symmetric Key algorithm. So give "input128" as your input. Then debug the code to see what it generates after applying the algorithm on "input128". That would be the original input you have ...
  • 119

Only top scored, non community-wiki answers of a minimum length are eligible