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Questions tagged [deobfuscation]

Techniques to remove obfuscation from a piece of program.

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68
votes
9answers
64k views

Analyzing highly obfuscated JavaScript

I was recently analyzing a web page that contained some highly obfuscated JavaScript - it's clear that the author had went through quite a bit of effort to make it as hard to understand as possible. I'...
60
votes
8answers
175k views

How do I reverse engineer .so files found in android APKs?

I know how to reverse engineer normal android APKs using tools like APK-tool anddex2jar but i don't know how to work with obfuscation. Can anyone help or atleast provide some pointers? I know this ...
21
votes
4answers
5k views

What is “overlapping instructions” obfuscation?

I analyzed some binaries in x86/x86-64 using some obfuscation tricks. One was called overlapping instructions. Can someone explain how does this obfuscation work and how to work around?
12
votes
1answer
89k views

How to deobfuscate an obfuscated javascript file like this? [duplicate]

I'm having serious problems deobfuscating a JavaScript file at work. This file is inside a web app that I was left in charge to improve it. The problem is that I can do it without having access to ...
10
votes
4answers
19k views

Try to deobfuscate multi layered javascript

According to the techy zilla blog It will be much harder to deobfuscate code that has been obfuscated using multiple obfuscating algorithms. According to them, jsbeautifier can't fix this obfuscated ...
10
votes
2answers
4k views

What are the available libraries to statically modify ELF executables?

I would like to be able to rewrite or reorganize an ELF binary program directly from the executable format (not at compile-time). The only library I know to do this is elfesteem (used in Miasm). But,...
8
votes
3answers
9k views

Guessing CRC checksum algorithm

I am trying to reverse engineer a 16 bit checksum algorithm of one relatively old (10 years) LAN game that is no longer supported nor has source code available. As it seems, data packets don't have ...
6
votes
2answers
4k views

How to find file compression or obfuscation type

The program I'm trying to decompile uses several supporting files: somesound.mp3 someimage.jpg etc.. The files are all located in the file system, not embedded into the exe. The files are used at ...
6
votes
1answer
392 views

Simplifying assembly

I'm analysing some binary trace, it's pretty much obfuscated. What I need to do is to understand work flow of its alghoritms. However I cannot find any reliable tool which would help me with that. I ...
6
votes
1answer
569 views

Recompiling/optimizing redundant code to make analysis easier

I'm analyzing an application created with Borland Delphi but the poor quality of the object code makes analysis difficult and tedious. The code is so convoluted and inflated with superfluous ...
5
votes
1answer
1k views

How can I decode this php code?

I found this backdoor on a client's website. http://pastebin.com/wVs8w44v (original format) http://pastebin.com/acfx49QJ (semi - readable) I have gotten rid of it and realise it's an obfuscated ...
5
votes
2answers
374 views

Formal obfuscation

My question is related to this question with the excellent answer of @Rolf Rolles. Since the paper of M.D. Preda et al is quite technique so I wonder whether I understand their idea or not. The ...
5
votes
1answer
1k views

How to efficiently simplify obfuscated formula in QF_BV logic with Z3?

I would like to know if there are efficient ways to simplify arithmetic formula expression over bit-vectors with Microsoft Z3. But, first, I would like to explain a bit the problem. Lets start with an ...
5
votes
1answer
2k views

IDA PRO Hex-Rays 1.5 pseudo code understanding -=0x3FFFFFFFu; += 0x3FFFFFFFu;

I'm trying to clean up the pseudo code to make it compile and function similar if not exactly the same as the original code. This bit which looks like this appears in various places I'm trying to ...
4
votes
2answers
288 views

Need help in figuring out checksum used in this small wireless packet

Need help in figuring out the checksum used for this small data packet. Packet is 48 bits long, I already have figured out most of the bits. Least 8 bits change even if there is a single bit change in ...
4
votes
3answers
203 views

Obfuscated code analysis - can unused variables be ignored?

I am analyzing a malicious javascript. The code is encoded and obfuscated in a way that I did not manage to even partially deobfuscate yet and it is filled with long strings. In order to simplify the ...
4
votes
1answer
818 views

Protect a key from being recovered by decompilation

I work in a game editor that develop an online game. In our endless struggle against bots (that have negative impacts on server performances, game economy, game experience, ...), one of ours weapons ...
4
votes
2answers
970 views

Automating pattern-based de-obfuscation of x64 code using IDA plugins

Trying to deobfuscate x64 code. You can skim/skip most of this, since it mainly exists to prove I have tried and exhausted all avenues. Burning Purpose To massively automate the deobfuscation within ...
3
votes
1answer
465 views

Animal Crossing: Pocket Camp .zdat File

Hello I am trying to obtain the music from the new game Animal Crossing: Pocket Camp. The music is contained in files like these: https://download-cdn-ac-pocketcamp.akamaized.net/assets/...
3
votes
2answers
100 views

Hardcoded addresses in dumped PEs

I have taken a dump of a game using Explorer Suite, and while looking at some obfuscated parts of the game PE's text section in IDA, I've seen code that follows this form: mov rbp, 7FF633CE2790h jmp ...
3
votes
1answer
2k views

Rename classes and packages in a jar file

I have an obfuscated jar file I'm trying to decompile and get into an eclipse project. I can easily view the "source" using a tool like jd-gui but I cant save it because the filenames are too long. I ...
3
votes
1answer
784 views

On the indistinguishability obfuscation (informally)

I have some superficial thinking about the indistinguishability obfuscation, these come from this question of @perror and the answer of @mikeazo herein about a construction of the indistinguishability ...
3
votes
1answer
726 views

How to deal with heavy control flow flattening?

I am trying to reverse engineer an executable that uses a lot of control flow flattening obfuscation (i.e, lots of subroutines that end with something like jmp esi, jmp eax) IDA Pro isn't able to ...
3
votes
1answer
400 views

Experiences from reverse engineers in detecting recursive calls

I have absolutely no experience in reversing real-world binary codes, so I wonder how the obfuscated codes prevent reversers. I doubt that the reverses always find some ways to understand what are ...
3
votes
1answer
5k views

Analyze obfuscated JavaScript code? [duplicate]

I have this code var _8818;var _7347='...
3
votes
0answers
443 views

Deobfuscate PHP that contains - goto

I've found a bunch of obfuscated PHP scripts in my server but it seems I cannot deobfuscate them to follow the code flow. I came to the conclusion that the files have been obfuscated with https://www....
3
votes
1answer
1k views

Understanding AutoIT “compilation”

I'm trying to de-compile a cheat created for my game so I can fix it. The problem is the version used is 3.3.14.2 which no longer has official de-compiler support. I have tried looking for 3rd party ...
3
votes
1answer
547 views

Reversal of unknown obfuscation or encryption with known plaintext

Introduction For academical reasons I am reversing a firmware for an embedded device. I have already created a perl script which is able to parse the firmware structure and extract files from it (its ...
2
votes
3answers
5k views

Extracting classes from running JVM

I'm trying to RE a Java application that uses an obfuscated loader program to load classes from a second, obfuscated archive-like file. I'm trying to get at these loaded classes for further analysis, ...
2
votes
1answer
958 views

What kind of compression/obfuscation algorithm is this?

I have a couple of streams that look pretty odd within a DICOM file. In a few words, DICOM is very close to what binary XML would look like. Almost all of the information from those DICOM files are ...
2
votes
1answer
1k views

Any good deobfuscators for java?

So I've built an obfuscator for java source code, would anyone know if there is any good deobfuscators which i could test how well my obfuscator is? I know there are many deobfuscators out there, ...
2
votes
2answers
3k views

Deobfuscating a javascript file

I am having a obfuscated JS file and I want to deobfuscate it (and not beautify it). I have seen answer to a similar question here and I tried de-obfuscating a the file using online version of ...
2
votes
1answer
2k views

Deobfuscating IDA Pseudocode

I have wanted to get into the art of reverse engineering for quite some time now, so I took a look at a few online lessons (such as opensecuritytraining.info) and also got my hands on IDA Pro. ...
2
votes
1answer
493 views

Decoding Malware javascript [closed]

My .php and .js files have been attacked twice in a month with some JavaScript code. After going through this similar thread, I ran the JavaScript code posted there and found this decoding result. ...
2
votes
1answer
125 views

Find out string encoding/shift of proprietary binary file format

I'm trying to reverse-engineer a proprietary file format to be able to extract certain strings from files in this format. I have the application, that writes the files, at hand. By trial-and-error I ...
2
votes
1answer
770 views

IDA 7.0 (freeware) auto-analysis gets stuck in a loop

I am trying to create a graph so that I can visualize the flow of a particular function in a game that I am interested in. I was initially using Cheat Engine to follow the flow of the function, but ...
2
votes
2answers
142 views

How to call an item of a Javascript array?

Say I have the following Javascript array: var _0xe984=[ '\x61\x70\x70\x6c\x79', '\x72\x65\x74\x75\x72\x6e\x20\x28\x66\x75\x6e\x63\x74\x69\x6f\x6e\x20\x28\x29\x20', '\x7b\x7d\x2e\x63\x6f\x6e\x73\...
2
votes
0answers
570 views

How to decompile a obfuscated mach-o dylib?

I am trying to decompile a dylib called libConfigurer64.dylib, which is loaded from the environment variable "DYLD_INSERT_LIBRARIES" I want to analyze what it really does, so I dragged it in to IDA,...
2
votes
0answers
2k views

Tool for JavaScript deobfuscation

I'd like to reverse engineer a JavaScript program by manually renaming minimified variable, parameter and function names. However, updating my reverse-engineered code to a newer version would be very ...
2
votes
0answers
864 views

Do any known deobfuscateors work on Agile.net 6.4?

As a company we are going to start obfuscating our released binaries, so far the best front runner we have found has been Agile.net 6.4. I took one of our binaries we obfuscated with the trial ...
2
votes
0answers
535 views

find CRC algorithm, having some input and output data pairs

I'm trying to discover the algorithm of a lost software, there is an equipment that requiest some data, and validates the data using the "KEY", if you change any parameter of the data then you need a ...
2
votes
0answers
166 views

Javascript equivalent of JEB

In case you already know, there is a full-feature decompiler for Java/Android called JEB (https://www.pnfsoftware.com/) Some of the most important features include the ability to rename identifiers ...
1
vote
1answer
2k views

What kind of obfuscate is this?

I'm trying to deobfuscate a .NET exe file, using de4dot. I have many dll files, when I open the dll file with .NET Reflector, it appears like this: And when I did the deobfuscation again with de4dot, ...
1
vote
2answers
2k views

(de4dot) The file isn't a .NET PE file

Probably, many of you have ever seen the message from de4dot while trying to deobfuscate app/dll: WARNING: The file isn't a .NET PE file: What steps to take in such cases to proceed? How to make the ...
1
vote
2answers
607 views

Debugging Win32.Upatre - why does Ollydbg fail to analyze this?

So I've been looking at this thread - Where can I, as an individual, get malware samples to analyze? And grabbed myself a binary sample of Win32.Upatre from Halvar Flake's blog. I started analyzing ...
1
vote
1answer
2k views

Is deobfuscation of my javascript code hard or easy?

I am trying to protect my app code from theft. Since most of it is written in javascript I had to use many obfuscation techniques to make it incomprehensible. I have written a very small piece of ...
1
vote
2answers
658 views

how to deobfuscate Autoit strings?

The code is: https://pastebin.com/ZwvySjgy Is it possible to deobfuscate the strings protected with STRINGDEC?
1
vote
1answer
3k views

Decompiling and deobfuscating APK file

Let's suppose that I have an APK file. I decompiled it but I have very obfuscated code. Is it possible to analize this APK in such way that application will be executed step by step (instruction after ...
1
vote
1answer
642 views

How to get address where MakeFunction() failed in IDA Pro

I am analysing obfuscated code which contains code paths leading to dummy instructions. These dummy instructions prevent IDA from creating functions. However, I need these functions to do a function ...
1
vote
2answers
5k views

How do you deobfuscate Java classes? [closed]

What tools or methodology do you use to de-obfuscate Java classes? I know you can theoretically decompile, modify and recompile, but that's only you fully trust a Java decompiler (and none is ...