Questions tagged [obfuscation]

Concealing the nature of how things truly function or work.

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18
votes
3answers
4k views

Anti-debug techniques on Unix platforms?

I am trying to scan all possible techniques to disrupt the usage of a debugger on a Unix platform (ie POSIX and a bit more). I am thinking about techniques such as the PTRACE test at the beginning of ...
1
vote
2answers
89 views

Wave File obfuscation

I have this file here, that is supposed to be a wave audio file, but seems to have some obfuscation applied to it. The file header is here: https://pastebin.com/LD5aA1EG Any suggestions where else ...
65
votes
8answers
212k 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 ...
36
votes
5answers
6k views

What is the reason for this method to call itself?

While reversing a 32bit Mach-O binary with Hopper, I noticed this peculiar method. The instruction on 0x0000e506 seems to be calling an address right below the instruction. What would be the reason ...
0
votes
0answers
44 views

.NET - What kind of obfuscation is this?

I'm currently performing some malicious DLL malware analysis, and I'm having some issues figuring out how to de-obfuscate this particular sample. It uses a lot of Reflective Assembly calls, and, a lot ...
23
votes
2answers
11k views

What is a “control-flow flattening” obfuscation technique?

I recently heard about the "control-flow flattening" obfuscation which seems to be is used to break the structure of the CFG of the binary program (see Diablo obfuscation module and Symbolic Execution ...
0
votes
0answers
132 views

What are the known techniques used by wrappers and obfuscators to protect against decompiling?

I am NOT looking to make my application 99% safe, nor my goal is to prevent a a determined reverse-engineer to disassemble it, but simply is to protect my source code from lambda user with little ...
1
vote
0answers
82 views

Guidelines for dealing with obfuscated code

I have taken a deep dive into reversing software with IDA, I used Ghidra before. I have already solved a couple of basic crackmes now I have targeted another one which's code is obfuscated, also has ...
2
votes
2answers
143 views

Virtual machine code obfuscation implementation details

I want to implement a VM based simple proof-of-concept obfuscator. It should take an exe file as input and produce a new pe file with appended vm section. For simplicity let's say the exe file is ...
5
votes
3answers
2k views

What is this obfuscation method called?

I have recently seen the following code obfuscation method: ... jump loc_1234 ;------------------------- Bunch of junk ;------------------------- loc_1234: code continued... The logic ...
0
votes
0answers
78 views

Obfuscated and/or encrypted firmware?

I own 3 samples file of a firmware but I can't determine if it's obfuscated and/or encrypted. Could you give some hint about it? Here is the following samples: Sample 1 Sample 2 Sample 3
1
vote
0answers
55 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 ...
0
votes
0answers
52 views

What type is this obfuscation ? (iOS Dylib)

Someone published a patch/crack for my iOS app. I wanted to know what does the dylib but it seems to be heavily obfuscated (all strings are obfuscated too). You can see some screenshots below. Can ...
1
vote
1answer
115 views

Reverse Engineering Java - Deobfuscating symbols

I'm new to Java and working on cleaning up a fairly large Java .jar sample where the obfuscator has renamed symbols into invalid names. For example: import org.lib.00.0.2; public final class 90 ...
0
votes
0answers
32 views

How to call strongly encrypted DLL from Resources?

There is a program. This program accepts plugins. Plugins written with C#. I have to encrypt it. But when I use strong obfuscators I have exception. Program doesn't read. How can I fix that ? How can ...
18
votes
4answers
9k views

What is an “opaque predicate”?

I saw the term of opaque predicates several times in obfuscation papers. As far as I understand it, it refers to predicates that are hard to evaluate in an automated manner. Placing it at strategical ...
2
votes
1answer
3k 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 ...
2
votes
0answers
115 views

How to reverse engineer an exe built using nexe?

I am working on an express application. I obfuscate the source code using javascript-obfuscator. I am using nexe cli for generating a single exe from the obfuscated code. Can anyone tell me if there ...
-1
votes
1answer
171 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 ...
2
votes
2answers
920 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 ...
1
vote
1answer
186 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 ...
1
vote
1answer
127 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 ...
1
vote
1answer
222 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/...
0
votes
1answer
150 views

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 ...
1
vote
0answers
43 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 ...
2
votes
2answers
336 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 / ...
1
vote
0answers
74 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 ...
0
votes
0answers
47 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 ...
1
vote
1answer
104 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 ...
5
votes
2answers
526 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/...
10
votes
4answers
21k 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 ...
9
votes
5answers
18k 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 ...
1
vote
3answers
4k views

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 ...
0
votes
2answers
1k 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: ...
0
votes
0answers
694 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 ...
60
votes
6answers
27k 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 ?
1
vote
0answers
183 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 ...
1
vote
0answers
46 views

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 ...
1
vote
1answer
1k 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 ...
2
votes
1answer
164 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 ...
2
votes
2answers
434 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....
1
vote
1answer
369 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
votes
1answer
464 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 ...
1
vote
1answer
1k 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 ...
1
vote
0answers
356 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. ...
11
votes
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: ...
7
votes
2answers
455 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 ...
1
vote
1answer
599 views

What is the difference between stripped binary and obfuscated binary

I want to know the difference between stripped binary and obfuscated binary.
1
vote
0answers
1k 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 ...
4
votes
3answers
252 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 ...