Questions tagged [obfuscation]

Concealing the nature of how things truly function or work.

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De-obfuscate JS code

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 ...
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2answers
175 views

Dealing with heavily obfuscated Java, possibly on bytecode level

I've got a jarfile from a friend, he told me to put it thru an decompiler. So I did, but: JD-GUI basically spit out just the imports and didn't show any class data CFR dumped out stack trace on ...
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1answer
97 views

Stack-pointer analysis failed

I'm testing my toy obfuscating C compiler against IDA's decompiler, but IDA refuses always functions (then the decompilation is not possible). For example, at one of lowest-levels of obfuscating, a ...
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1answer
53 views

Python self decryption script, as mean of obfuscation

I have a software with an embedded python interpreter. The software can open upon startup a given .py script and execute it. Let's assume that in my python environment I can't open other files, and I ...
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1answer
152 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/...
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1answer
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Error After de4dot - Application Does Not Start

There is an application that has been obfuscation to learn. So in an unpack me style. In the first stage I would unpack with de4dot. After you unpack, the running application stops working. dump and ...
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40 views

Possibly infected image

Long story short I'v downloaded a template for my website and instead of images it has the .html files included, and at the beginning those html files do include PNG IHDR , and they are being loaded ...
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2answers
154 views

Static analysis obfuscated code

I'm reversing a code that is heavily obfuscated. It uses opaque predicates, call stack tampering, junk code and control flow flattering. Call stack tampering uses indirect branches (push register / ...
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67 views

API Hiding Issue

I'm trying to analyze a malware which is hiding API names. When I open it with CFF Explorer, except a few API like GetProcAddress, nothing appears. Basically, I know how API hiding works. I set a ...
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1answer
184 views

Best way to protect source code of .exe program running on Python?

I am developing proprietary software that would be distributed in a form of .exe file. In order to use it, users will have to authenticate with their whitelist credentials (username + password). The ...
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34 views

IDA Fails to Analyze Stack Pointer Correctly in Heavily Chunked Functions

I am currently dealing with obfuscated code in IDA. The obfuscation I am combating is control flow obfuscation, where a function is split up into hundreds of basic blocks spread across the entire ...
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1answer
62 views

J2ME games obfuscator - Spyro and Tekken 5

While reversing some J2ME games like Spyro or Tekken 5 Mobile I have encountered a weird obfuscation where all fields, methods and classes have names like A, a, B, b, Aa, Bb etc. It's really hard to ...
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221 views

Trace Method Calls in .NET/C# Binary

I have a heavily obfuscated Windows service binary. Fields, types and methods are renamed. While it is possible to decompile the binary using dnSpy, it is still very cumbersome to identify important/...
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4answers
20k 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 ...
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5answers
17k views

What are the techniques and tools to obfuscate Python programs?

This question is related to this other one. I just wonder what are the techniques applicable and which can be found in the real world to obfuscate Python program (similar questions can be found on ...
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3answers
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How to obfuscate x86 assembly code?

For my project, I am performing a kind of checksum operation on a portion of code to protect it and therefore do not want its template to be easily visible and therefore need obfuscation. I have ...
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2answers
833 views

verifyError in youtube android app modification

I try to decompile youtube android application and modify it but when I build the application and install on a virtual device faced with below error: E/AndroidRuntime(1782): java.lang.VerifyError: ...
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180 views

Obfuscate JSON file that is served client-side

Through some research I have found that obfuscation won't block hackers from retrieving your .json file, but I'd like to have at least a level of obfuscation that deters some people. I ran into a npm ...
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37 views

obfuscating mprotect, or run-time alternative

For an anti-debug method, I need to make a stack page executable at run-time, but only briefly. I don't want to use mprotect() as it's easily located and tracing forward reveals the location of the ...
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6answers
24k views

Where to find (free) training in reverse engineering? [closed]

Can someone give a list of websites with good (and free) reverse engineering training exercises ?
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149 views

Mysterious chunk of code in IOLI crackme0x06 challenge

I've been struggling to understand a very strange piece of x86 assembly code from the IOLI crackme0x06 challenge. Context But first of all, here is the context : I've successfully cracked the ...
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106 views

Reverse engineering .NET malware - iloveyou.exe

I have a .NET malware sample whose dynamic behavior I understand. It is also packed. de4dot identified the obfuscator as .NET Reactor, so I used de4dot to de-obfuscate it. However, after de-...
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How to choose a .NET software protector which will have a small impact on run-time performance speed? [closed]

I am writing a .NET software which is doing calculations and drawing in real-time i.e when the user is moving the mouse. I want to protect this software from being reverse engineered and restrict its ...
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8answers
182k 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 ...
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1answer
735 views

How to deobfuscate native Android library obfuscated with OLLVM?

When I load the binay in IDA, all I can see are loads of .datadiv_decodeXXX... functions and this is because of OLLVM. I know it is possible as a Chinese article I found said they were able to ...
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37 views

Replacing a function call with it's result in a script

I'm working with a heavily obfuscated Autoit malware script and one of the major problems is that almost all variables and lines of code are obfuscated by a custom function. The problem is that this ...
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1answer
130 views

Does a symbolic disassembler exist?

I would like to know if there are disassemblers based on a symbolic analysis, I'm beginner in RE, but I think that a disassembler based on symbolic techniques can be very interesting and could ...
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2answers
254 views

Jump in the middle trick

I'm reversing a program that "hides" some instructions using the jump in the middle trick. This trick is a jump to a middle of an instruction, whereas the real address actually contains another opcode....
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1answer
224 views

What's this obfuscation technique?

I'm reverse-engineering a particular dylib on Mac OS X. The dylib is highly obfuscated, but I suspect it's from some well-known technique that I'm not aware of. I'd like to describe it in the hope ...
6
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1answer
406 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 ...
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1answer
625 views

Analyzing and deobfuscating complex JS code [duplicate]

I am looking to reverse engineer a very ugly piece of JS found here. As far as I can tell, this script generates and sets some cookies on my browser that identify it on the site. Deobfuscating it ...
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0answers
279 views

C# Hidden Method through transparent proxy object?

I'm dealing with an interesting form of obfuscation. A C# program I am reversing has a central API, let's call it "Central API". This Central API has several functions that aren't exactly defined. ...
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2answers
2k views

Protect data stored in binary

Let's say I've some function(i.e. hash function), that generates value from input seed and some precomputed hash values, that are stored somewhere in binary. What are the possible approaches for: ...
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2answers
393 views

Why do obfuscators remove line numbers, and can I safely leave them in?

Application security engineer here. When we compile our java code, we obfuscate it using KlassMaster and have it remove line numbers (see KlassMaster docs) because of a handwavy explanation "it makes ...
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1answer
378 views

What is the difference between stripped binary and obfuscated binary

I want to know the difference between stripped binary and obfuscated binary.
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0answers
913 views

Can de4dot deobfuscate Dotfuscator Professional?

I ran de4dot on a Xamarin app obfuscated using Dotfuscator Professional. However, there's still the random switches and strange ints everywhere. Can de4dot decode this? If not, is there another tool ...
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3answers
221 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 ...
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0answers
54 views

Missing Map from Java Native Method to C Code

When writing a C implementation for a native Java method in Android, the rule is to name the C function according to the convention "Java_com_...". But I encountered an APK in which there are no such ...
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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 ...
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0answers
364 views

Obscure router refuses to flash OpenWrt

This is a very obscure Chinese router from a brand called Wavlink. It's the Model: WN529R2/WN529R2P. It's web interface was pretty limited and wouldn't allow firmware modifications. I found GND/Tx/Rx/...
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2answers
203 views

Why doesn't this retn instruction return from the function?

I disassembled an exe file on Windows with IDA and saw this function prologue: I see that when the retn executes instead of returning it jumps to sub_1314cba4. Why doesn't the retn instruction ...
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2answers
679 views

Android App's hardcoded local keystore password r3versing

Novice Android security researcher here. Recently I was tasked with the task/challenge of exposing a certain app's hardcoded local keystore password. I've decompiled it with JEB2 and obviously within ...
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1answer
6k views

How do I decode this JavaScript code? [duplicate]

Each file starts with the same function: (function(_0x128f83, _0x1ae5b9) { var _0x1b5471 = function(_0x339be5) { while (--_0x339be5) { _0x128f83['push'](_0x128f83['shift']()); ...
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1answer
394 views

Map an obfuscated javascript file to the original

Among other approaches, there are ways to "prettify" obfuscated javascript. But most of such approaches are geared towards someone trying to understand code that's not their own (e.g. from a website, ...
3
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1answer
335 views

IDA pro obfuscation instance

I have tried all the I have learned so far to figure out how to deal with this instance of obfuscation. So far I understand that an opaque predicate is present, causing an unconditional jump to one ...
3
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1answer
482 views

Deobfuscating overlapping x86 assembly instructions

I'm trying to solve a reverse engineering challenge (http://crackmes.cf/users/beatrix/beaba/) and am having trouble with the obfuscation. Below is a piece of code that gets executed almost immediately ...
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2answers
859 views

Is there a name for this kind of “obfuscation” for the machine code from C++?

I was trying to reverse engineer an android ndk (arm) using ida pro on a static analysis. However, it appears there are a lot of useless jumps to the same place and with random values set to R1 to ...
3
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3answers
3k views

Exe protection by TLS callback, trying to understand the behaviour

I have an app, obfuscated by FSG protector. When i tried to unpack it, the first thign that i had is, when i start the process with the debugger/or attach debugger later, i immediatly receive ACCESS ...
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1answer
481 views

ARM ELF Obfuscation [closed]

Metamorphic is a technique to obfuscate a binary and change the opcode sequence and create new samples with same functionality. In my case, I have some elf binary of ARM processor type and their ...
12
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1answer
92k 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 ...