Questions tagged [java]

Java is an object-oriented language and runtime environment (JRE). Java programs are platform independent, because they are compiled to bytecode and their execution is handled by a Virtual Machine called the Java VM or JVM.

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Java Byte Code Debugger

I'm trying to reverse a highly obfuscated program written in java. None of the deobfuscators seem to work so I have been poking at it in eclipse. I can attach to a running process and have figured ...
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1 vote
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Java bytecode dynamic analysis

I've been trying to patch a certain functionality of a jar file, that's essentially a GUI app. I've tried numerous java agents -as it seems to be the only viable option for java- for such a task, ...
2 votes
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How do I log a string in smali without its obfuscated function?

I'm reversing engineering an app and after analyzing with man-in-the-middle, I find that it obfuscates its messages to the server so it looks like a gibberish. String stc = ("msg=" + ...
1 vote
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frida cant cast string array to java.lang.object

i have a java method i am trying to call manually public static native Object a(int i, int i2, long j, String str, Object obj); the last parameter is a string list casted to java.lang.object the way ...
2 votes
1 answer
136 views

Automatic deobfuscation of Java class/method/parameter names with access to old non obfuscated sources

I am currently trying to de-obfuscate a Java program (i.e. find each class name and namespace, each method name and each method parameter name). To do so, I started by using Enigma (the fork from ...
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Where can I find the hashing algorithm in source code?

When I submit login credentials in an Android Application it POSTs an encrypted string to an API endpoint. For example, if I enter the following email & pass : "abc@abbc.com:abc" it ...
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1 vote
1 answer
113 views

How to set a breakpoint in android's openssl library in running android application?

I'm debugging an obfuscated android application. I use Android Studio's debugger. I attach it remotely to my physical device via adb. I can set a breakpoint in the app smali code, but when I try to ...
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0 votes
1 answer
592 views

frida returning wrong overload of android method

im trying to hook the C6494a method has 2 parameters the ge6 object and a activity object whenever i try to hook this method with a hook overload that contains both ge6 and the activity object frida ...
0 votes
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Mod Coder Pack for minecraft 1.8.8 failed to decompile

I tried to decompile minecraft 1.8.8 using MCP918 and I have an error that I cannot fix. Here are the logs: https://zerobin.net/?07c9671c16bc4011#g6co8FZc8RJkkQiPb6pu65HixcEORkWZGN8qHPXkHew= Some ...
1 vote
1 answer
632 views

[Ghidra]How to set global variable type?

I have created a script in Java and I have a structure type as a string name which I want to set at given global variable which I have the Address of. However I can't seem to find a way to do this - ...
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1 vote
1 answer
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How to utilize `FillOutStructureCmd`?

Basically I'm extending the CreateStructure.java plugin so it iterates all functions and tries to automatically create structures on all variables. It looks something like this: public class ...
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1 vote
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Where can I find the encryption algorithm for this POST request in an Android APP?

I have an Android app for which I need to mock an API call outside of that environment. I successfully killed the certificate pinning on this app with Frida in order to access the URL and more, but ...
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1 answer
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Decompile obfuscated jar file

Tried java-deobfuscator and other things, detect said it was allatori protected so tried the relevant transformers but to no avail. Please can someone help, I'm happy to tip for your help :) https://...
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213 views

Trace java calls from a native library using frida

Im trying to trace method calls from a native library using frida I've tried jnitrace but it won't print anything Do you have any suggestion?
1 vote
1 answer
713 views

Where can I find the encryption algorithm in source code?

When I submit a Customer Reference ID in an Android Application it POSTs an encrypted string to an API endpoint. For example, if I enter the following CR ID : "SR-54585482" it POSTs the ...
0 votes
1 answer
244 views

SQLite access from Ghidra script

I would like to access an SQLite database from within a Java Ghidra script. However, if I include the line import java.sql.*; in the script, Ghidra gives the error > Unable to locate script class:. ...
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What is this CRC32 algorithm (written in C), and how can it be written in Java or Python?

I've been trying to convert this CRC32 algorithm to Java or Python, but I haven't been successful, I believe it's because I'm not familiar enough with c. Note that I believe DAT_804818d0 is the seed, ...
5 votes
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294 views

Patching Jar File (2022)

Currently reversing a .jar program recreationally, and I understand the workflow proposed here: https://www.netspi.com/blog/technical/thick-application-penetration-testing/patching-java-executables-...
3 votes
1 answer
273 views

Determine if exe is written using Java

I'm examining my Windows programs to determine which ones are written in Java, and if so, whether they import a log4j library affected by the log4shell vulnerability. Programs that are packaged as JAR ...
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1 answer
434 views

Ghidra: Iterating over function's codeUnits returns only 1st instruction

public void run() throws Exception { var cp = currentProgram; var nsSymbols = ghidra.app.util.NamespaceUtils.getSymbols("myNameSpace", cp); var glNS = nsSymbols.get(0)...
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How to deobfuscate Java application

Hi i am unable to deobfuscate the Advanced String Obfuscation Jar on tryHackMe I tried dumping the classes using a dumper javaagent deobfuscate the jar with java-deobfuscator threadtear functions ...
1 vote
1 answer
109 views

Java Malware Dollar Sign

I am analyzing a mobile malware sample and got a trouble. When i put sample in JADX, i see some dollar sign. I mean like this; What does these dollar signs means?
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41 views

Capturing created and deleted files from a Java file

I am new to the malware analysis field but I do have an issue, a file I am working on creates 2 vbs files, reads from them and deletes them, this all happens in around 2 seconds. Also this is a Java ...
0 votes
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Checksum verification of an apk does not the same as my java program

I'm from the sysadmin side of the IT and have not much experience in programing. I have an app that lets me screen share Android apps on my car's display. Sadly there is a whitelist baked into the app,...
0 votes
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108 views

Is this native code possible for further static analysis?

I was trying to reverse engineer a native lib code in an android app. the .so contains many functions. But the function sUQWWyTBEs() was referred in the Java code. I was curious how this function ...
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-1 votes
1 answer
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what do these assembly code doing?

I tried to reverse engineer an apk app, and it was loading a native code. I have observed that the app was using the native code like this public static String v = sUQWWyTBEs().toString().substring(32,...
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1 vote
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What tools can be appropriate to reverse engineer a (open-source) java program?

I am very new reverse engineering, and have the below mentioned tasks to achieve on a open source program called Apache Ant. What (preferably free) tools can be appropriate to achieve these. I have ...
0 votes
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131 views

How do I decode or decompile this class It seems codes are encrypted?

I've used JD-Gui, Luyten and other couple of Java Decompilers but it's not working what is the problem in here? Thanks! It's A Mod (Minecraft) and I'm porting into different versions. Code: public ...
2 votes
1 answer
1k views

How to decompile heavily obfuscated classes mixed with Arabic/Chinese/Korean characters?

I recently downloaded a jar file and was curious to see if it was malicious, so I ran it through FernFlower and it wasn't able to deobfuscate it. When I unzipped the jar, I looked inside it and saw ...
1 vote
1 answer
214 views

Java Help Understanding RSA Encrypt/Decrypt file and SD card

I was directed this way from the main superuser site: I have zero experience with Java or Android apps (I have coding experience in C) and tried reverse engineering a [now defunct/unsupported] app ...
3 votes
2 answers
1k views

Frida reading files is slow

I need to read a file around 2 MB into a byte array. var fis = Java.use("java.io.FileInputStream"); var file = fis.$new("/data/local/file.txt"); var fileBytes = new Uint8Array(file....
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2 votes
1 answer
501 views

Making a Android Toast via JNI, i.e. calling Java methods via JNI

Concerning the outputting of an Toast, I found that there are some ways to make a Toast, that invoke calling a FindClass on JNIEnv object with the android/widget/Toast parameter, but I found no ...
1 vote
0 answers
931 views

Tracing all (or most of) function calls in a specific Android app

I'm having a problem, where I'm trying to trace some function calls in an Android app, that uses JNI for about all of its work. More specifically, a function call, in JNI, that makes (IIRC Android ...
1 vote
1 answer
618 views

How can I see when a library is being called in Android?

Apologies for a beginner-esque question, but I am reverse engineering an Android application, that is most probably using the libusbhost.so library to interface with USB devices via Java Native ...
0 votes
1 answer
2k views

Recaf: Recompile disabled, can't edit

I've download recaf jar file and install JDK 8. When I execute it/start it, it all works fine with java -jar recaf-2.12.0-J8-jar-with-dependencies.jar. I open a class file also no problem. The issue ...
2 votes
0 answers
34 views

How can I tell whether or not a given library method is being referenced by a consumer program statically in OOP languages?

Preface: This question is about source code reverse engineering and static analysis. Meaning, there is no built code available but I have access to the source code of the program. Imagine I'm looking ...
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-2 votes
1 answer
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How to deobfuscate Java application protected by Java Antidecompiler [closed]

Here is some infomation I found from MANIFEST.MF Archiver-Version: Plexus Archiver Built-By: boonb Created-By: Apache Maven Build-Jdk: 1.8.0_231 Main-Class: JavaLauncher Modified-By: 9.4 (BIS Guard &...
1 vote
1 answer
218 views

Accessing Call String of CALLOTHER Pcode Instruction via Java API?

Is there a way to access the call string of a CALLOTHER Pcode instruction when iterating over the Pcode in Java? The listing below shows an example of what I mean: 048 ...
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2 votes
1 answer
785 views

How do we decompile java so easy?

I have seen a lot of videos where everyone is decompiling the jar files so easily. but I learnt that we cannot decompile any compiled file so easily. I have a little bit of experience in Gidhra. I ...
1 vote
1 answer
373 views

frida - The specified child already has a parent. You must call removeView() on the child's parent first when hooking, how do you solve it?

I wanted to hook the method A1f in the below code but frida returns the following exceptions: Found instance: MyHomeFragment{9bbd8d5} (0965bca9-4838-4ca1-a835-d99639ae15f1)} java.lang....
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-2 votes
1 answer
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how to deobfuscate to java zkm?

I will have a question for you, dear forum residents. I have a .jar file encrypted with ZKM which I think will work for me. I don't know how to decrypt this, can you help me?
1 vote
1 answer
739 views

Calling a method of a Java object passed as argument to hooked function in Frida

I am trying to obtain the SecretKey passed to the decryptAesCipherText function. I hooked the function in Frida to try to print out the arguments when the method is called but since SecretKey is an ...
2 votes
1 answer
1k views

How to Launch and debug Ghidra from Eclipse with two Modules I'm developing at the same time?

Ghidra comes with its own Eclipse extensions that allows you to develop new Scripts and Modules for Ghidra. I'm working on several new Modules for Ghidra that will work together. But I've basically ...
1 vote
2 answers
474 views

Working with strong obfuscated Java

I've got a jar file, that is strong obfuscated. When I tried to put it into decompilers such as bytecode-viewer and luyten I seen many lines of traps and Chinese letters. I tried to deobfuscate it ...
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3 votes
1 answer
897 views

Dynamic analysis (Frida) reveals instance of a class that doesn't exist in the source code (dex2jar)

I have been diving into an apk's source code, doing both static analysis with Jadx (same as dex2jar) and dynamic analysis with Frida. I am trying to replicate the method that signs HTTP requests "...
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0 votes
0 answers
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Hashing algorithm of length 50

I have been trying to reverse-engineer an Android application using Jadx for static analysis and Frida for dynamic analysis. The end goal is to be able to re-create the request signature, sent as a "x-...
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1 vote
1 answer
365 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 ...
1 vote
1 answer
608 views

How can I get classes from "protected" JAR file?

I'm trying to get classes from JAR file / actually running JVM machine but: When I'm trying to open JAR file using for example 7Zip I dont see any classes. After unzip Manifest file is empty too. When ...
3 votes
1 answer
408 views

How can I retrieve the encryption key in this code?

can anyone explain the following code? is it possible to retrieve the encryption key? I think the code was heavily obfuscated in addition to obfuscation, I can recognize it is using algorithms like ...
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1 vote
0 answers
150 views

JEB Decompiler - Signature recognition engine

I've been playing around with the JEB decompiler and Android reverse engineering suite. One interesting feature they have is deobfuscation by library code matching in which 3rd party libraries out ...
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