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Questions tagged [javascript]

JavaScript or JS is an interpreted computer programming language. It was originally implemented as part of web browsers.

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How to use reverse engineering to learn how facebook send messages?

I would like to know how I can use reverse engineering technique to learn how Facebook/messenger send messages? I were analyzing my developer tools network tab, but couldn't find anything. Fiddler ...
innocent98's user avatar
1 vote
1 answer
264 views

Convert string to byte array in frida js script

I am having an issue with a JavaScript script to be executed in Frida. In this case, I am intercepting an input from a function where I receive an array of bytes. I need to convert this array to a ...
VinixF's user avatar
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Reversing an obfuscated javascript library making heavy use of promises

I am reversing a little javascript library for my private use. This library is using promises to pass data around between different functions. This way, you cannot backtrack the function that is ...
user2276094's user avatar
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0 answers
41 views

Microsoft Teams web client: how does Teams knows if a device is allowed or not

In my company I am able to use Ms Teams only inside windows but when I try from a Virtual machine (Hyper-V) running linux it says that this device is not allowed. So how can the Teams Server knows ...
Vince Ricosti's user avatar
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1 answer
177 views

How do I deobfuscate this JavaScript? [closed]

link to the code: https://drive.google.com/file/d/1Y-M-gkYpzkrECh6gpsVyo_ZMO5ZMgdiW/view I tried using this site (https://lelinhtinh.github.io/de4js/), but it still accomplishes almost nothing youtube ...
CiNoP's user avatar
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1 answer
536 views

Deobfuscating big files

I'm trying to deobfuscate JS file, but it's to big for online services, like deobfuscate.io. I just can't copy content of file, because it have ~4M symbols. All deobfuscate services proccess file in ...
Peter's user avatar
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2 votes
1 answer
230 views

Tools to hook browser's Javascript function implementations

I'm wondering if there is a way to hook or inject code into Javascript's implementation of a native function. For example, print the calling parameters whenever an encrypt() function is called. I not ...
tur11ng's user avatar
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frida-example-agent npm run build not correct

I git clone frida-example-agent and run npm install and npm run build, but the output is wired, like below 📦 928 /agent/index.js.map 578 /agent/index.js 215 /agent/logger.js.map 58 /agent/logger.js ✄ ...
re100io's user avatar
2 votes
0 answers
72 views

Javascript: Compare Control Flow (to evade anti-debug and anti-tamper traps)

When reverse engineering obfuscated javascript, it may be protected by anti-tamper mechanisms. I have a script which will work when run untouched, but cause a fatal javascript error when run in node ...
Semnodime's user avatar
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3 votes
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91 views

How does google.com detect I'm in Firefox when already using Chrome's user agent

It's well known that google.com doesn't show the microphone search icon in Firefox, probably to incentivize people to use their web browser. (They give it on youtube.com, which is weird for being ...
Powereleven 's user avatar
2 votes
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79 views

Yelp: getting documentId for certain operationName

Going through devtools activity for this page (reproducible for any Yelp business page), there's a reference to a GetReviewSummary GraphQL operation in a javascript file. This data shows up in the ...
alpacafondue's user avatar
2 votes
1 answer
65 views

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

I am trying to debug an app which I don't own which uses HTML5 and JS, which displays a video stream. The issue is that the video stutters when viewed in high resolution. Note that the code is ...
KevinHJ's user avatar
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2 votes
0 answers
156 views

Access a XREFs with frida

I have a string which has a XREF to a func. This func changes of address at every updates of the app I am working on. So this string is the only "stable" point I can rely on to access to ...
hmngwn's user avatar
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2 votes
1 answer
542 views

frida hook `loc_*` or `sub_*`

Is it possible to hook a sub_... object in Frida ? I disassembled an arm64 executable, when running the app on my iPhone, I can see a lot of classes also in the disassembled executable, but I can't ...
hmngwn's user avatar
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2 votes
0 answers
27 views

Generating specific request cookies for a website

I have a script that autocheckouts products on a website (bot), recently the site seemed to update something and I keep getting 403 blocks(Perimeter X). My old solution was simply to rotate and brute ...
scraps's user avatar
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9 votes
1 answer
3k views

Decompiling an executable compiled by vercel/pkg

I have a .exe file that I am trying to get the source code of, After some digging I figured out that it's in node.js and was compiled using vercel/pkg I tried using pkg-unpacker however the output is ...
Anon's user avatar
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2 votes
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156 views

De-Obfuscating/unminifying a JS code [not duplicate]

I have come across a lot of similar questions on the same heading but unfortunately, none of them provided me with the intended results. I have a piece of code which, initially I am trying to ...
Supraja's user avatar
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1 vote
0 answers
27 views

Does anyone recognize this jQuery website plugin?

I am working on a site that was made years ago (not be me) and I need to identify a jQuery file manager plugin. This plugin shows a file manager view in a browser and allows the user to visually ...
colonelclick's user avatar
2 votes
0 answers
130 views

Frida hook InsertMenuItemW

I'm trying to get information about menu items in an application. Experimentally established that InsertMenuItemW is called. Thanks to the documentation, I set the number of input parameters and wrote ...
user123's user avatar
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2 votes
1 answer
328 views

'... Debugger undefined or null reference' error when WinDBG TTD Scripting with Javascript

I tried Javascript scripting on WinDbg (TTD specifically); but even in simple example I get error Unable to get property 'Debugger' of undefined or null reference. Line was simply var ctl = host....
DrawBacksYo's user avatar
1 vote
0 answers
233 views

How does one go about reverse-engineering obfuscated/minified JavaScript in a browser like you would code in an IDE?

I am trying to figure out how some minified and possible highly-obfuscated JavaScript works. There are thousands of lines spanning multiple JS files. I have had a lot of success debugging it in my ...
oscilatingcretin's user avatar
0 votes
0 answers
749 views

Bypass Javascript Debug Prevention in Firefox

I've looked around, and can't find an answer for my specific question. The closest I could find was this. I'm trying to reverse engineer some suspicious Javascript, but it repeatedly calls a debugger ...
Enki's user avatar
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1 vote
2 answers
4k views

Any good places to learn about JS de-obfuscation?

I am trying to make a bot on a specific website, so I have to reverse a lot of JS scripts. The reversing it self is not that hard but the de-obfuscation is. Lots of the scripts are obfuscated with ...
MoTheGreat's user avatar
0 votes
1 answer
214 views

How to clean obfuscated code from fake if statements?

I am trying to deobfuscate javascript code. Firstly I extracted strings from big array. Then I saw many parts like this There is only one line of code which makes sense. Is there any Node.js cleaner ...
Владимир Говорухин's user avatar
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0 answers
161 views

Confusion about if statement in disassembly

I recently got into reverse engineering applications for fun. Can someone please help me with this if statement. 140005914 75 38 JNZ LAB_14000594e 140005916 48 8b 4 MOV ...
fpena06's user avatar
  • 111
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0 answers
58 views

Disassembly a win Linux file

I have a file that has a compiled assembly code and being loaded into javascript code for execution. How can I “inspect” the file? I am aware of tools like immunity debugger or ollydbg but I am not ...
user avatar
4 votes
1 answer
237 views

Is there a tool to compare javascript files for differences, while also ignoring local identifier changes?

When trying to compare the difference between two minified javascript files with random identifier names, about 95% of the changes are identifiers being renamed. I would like to use a tool that ...
Camlan's user avatar
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0 answers
41 views

Methods to alert inappropriate use of JS code

Let's say we have a JS code library that is not for sale, just internal. Of course, anyone who can access the website will be able to download that and reuse it. To avoid others to reuse that library, ...
Ivan's user avatar
  • 101
2 votes
1 answer
90 views

automatically find the object "this" refers to in js

Im quite new to javascript and sometimes I find it really hard to find what object a keyword 'this' refers to. Is there a code editor that is able to do that for me? Or any other advice that could ...
Hukei's user avatar
  • 21
3 votes
2 answers
8k views

How can I modify or decompile Hermes JS bytecode?

Since React Native 0.60.4 developers can opt-in to use the Hermes JS Engine. This generates an index.android.bundle binary that contains Hermes JS bytecode. The Hermes documentation mentions hbcdump ...
irgendwr's user avatar
  • 133
3 votes
0 answers
277 views

Where to start with reversing a custom JavaScript VM?

I have recently ran into the most heavy JavaScript obfuscation I've seen. It is using a custom VM to execute bytecodes. I have never dealt with such obfuscation, and I am wondering where I can start ...
MapF120's user avatar
  • 31
0 votes
1 answer
61 views

What browser do during initial web page request?

I am trying to understand why if I do fetch() 4 times on the active web page, after the fifth fetch server returns response that I am a "robot" I am using google chrome I go the following ...
simply good's user avatar
2 votes
0 answers
499 views

How to get video file URL from Twitter

I am looking how to find the video URL of a Twitter video so I can code a converter later (using nodejs or something), but I can't figure out how to do this. I saw this but it doesn't really clear ...
Komali's user avatar
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0 votes
0 answers
205 views

How to locate the function being applied on password

I am thinking of taking up ethical hacking as a hobby. So, I installed Burp Suite Community Edition and set it up with Firefox. I opened Instagram and tried to login with these details (just for ...
Aditya Pratap Singh's user avatar
2 votes
1 answer
163 views

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

I was reading this Frida release page and noticed it made the following reference: Short of writing the whole agent in C, one could go ahead and build a native library, and load it using Module....
sherrellbc's user avatar
1 vote
0 answers
184 views

Intercepting packets from Electron App to keyboard in Linux

I have a USB keyboard which has an Electron app to set the macros on the keyboard. I unpacked the app.asar file, and the JS files seem to indicate that it is a ReactJS app, and is a minified ...
Sabyasachi Mukherjee's user avatar
2 votes
0 answers
100 views

Trying to replicate encryption of an android app

I was trying to replicate/copy the encryption of an android app which uses CryptoJS with sha256 encryption as having seen in the source code of the android app. fingerprinting the app, it was built ...
hanan's user avatar
  • 309
1 vote
2 answers
583 views

Reverse Engineering Javascript - Out of Memory

I found this javascript file on one of those online movie streaming services and was interested in finding out what it does. However, after trying many deobfuscators I am still stuck. A major ...
Christopher's user avatar
1 vote
0 answers
383 views

How to modify JS with mitmproxy?

I am trying to reverse engineer a heavily obfuscated web application, and I would like to modify the JS to add logging. So far, I've set up mitmproxy, but I can't figure out what the best way to edit ...
Antimony's user avatar
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-1 votes
1 answer
1k views

De-obfuscate JS code [closed]

I came across a script that converts font files from one type to another (i.e. WOFF to TTF, etc). I would like to understand it and incorporate some of the code into a personal project. The script ...
oldboy's user avatar
  • 99
1 vote
1 answer
308 views

Is it possible to completely reverse this code?

i have this code i'm trying to deobfuscate https://pastebin.com/g5mHpWE4 I used https://beautifier.io/ and http://www.jsnice.org/ but the result is still not good, current code: https://pastebin.com/...
Bruno Andrade's user avatar
0 votes
1 answer
12k views

How can I deobfuscate this javascript code

I am trying to deobfuscate this javascript code, but I don't know how it was created. Can you please tell me what the mechanism or the function is that generate such characters in javascript? É=-~-~[]...
Achraf's user avatar
  • 3
1 vote
0 answers
280 views

How to hook eval function in node.js

As the eval() function of JavaScript is an evil, I want to hook or monkey-patch eval() function of JavaScript in node.js. I want to intercept all arguments passed in eval() function. Please guide me ...
sumit_suthar's user avatar
1 vote
1 answer
125 views

What's wrong with my mitm to support rr commands with gdbserver on IDA?

First of here is the gdb remote protocol doc. The idea of the below script is the following - you enter an actual command (one that will be send as a direct packet see packets) in the gdb window then ...
rec's user avatar
  • 475
1 vote
0 answers
94 views

Need help reversing .m4t TTML subtitles format

I am currently trying to create subtitles for some proprietary Sony software. Unfortunatly, it only recognizes Sony's own .m4t subtitles format. After some research I found that this subtitles is also ...
R A's user avatar
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0 votes
1 answer
2k views

Decrypt config.bin file from Huawei B5328 router. I have source files

I need some help in decrypting the file config.bin generated by the page backup_setting.html from Huawei B5328 router. I have access to all files in the router, even the www files hosted on the www ...
coolirc's user avatar
  • 111
1 vote
0 answers
26 views

How to programmatically add HTML DOM breakpoints in chromium?

I've seen from this post about Chromium DevTools that there exists the possibility to add DOM breakpoints. Given that I've a full range of elements to monitor I was trying to find a way to ...
Gabrio's user avatar
  • 111
3 votes
1 answer
1k views

De-obfuscating code ran through JScrambler 3x via Eval() functions

I am relatively new to JS and de-obfuscation in general and I am having difficulties reversing some complicated JS. I know the code itself is obsfucated via jscrambler 3-4x and therefore is ran ...
Impensus's user avatar
1 vote
0 answers
176 views

deobfuscating/decompiling extremely complicated javascript [closed]

I am working with some extremely complicated JavaScript. It is around 70,000 lines long and sections of the code look like this U2xx.l11="0x78920d50";m2xx.r9G="11";b2xx.v3y="0x744ebc37";P2xx.K5h="...
Impensus's user avatar
0 votes
0 answers
78 views

javascript hook comparisons

Look at this very basic javascript code: if (s=='abcd') { if (s2='cdef') { ... } } I want to hook all tests: I want to get this: (s,'==','abcd') (s2,'==','cdef') Is there a way ...
Bob5421's user avatar
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