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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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-...
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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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Google Maps, Android serialisation format

I've come across an SQLite database (gmm_storage.db) used by Google Maps on Android, and I'm unsure as to how the data it contains is serialised. For example: I'm saying serialised, as from the ...
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How to reverse a java thread to get its origin

I was working on a java application which is run for the first couple of minutes & then application interface hangs. I had open the application in JMC & it shows later I create a thread dump ...
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Jar reversing: Can't open as zip file nor open it with common decompilers

I'm pentesting a JNLP application composed by several .jar files. I'm able to decompile with jd-gui every 3rd party library included in it, but the main .jar coded by my client. So after running JD-...
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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 ...
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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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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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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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1 vote
1 answer
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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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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 ...
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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 ...
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1 vote
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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 ...
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1 vote
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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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Some obstacles in reversing a JNI Native library

I deleted my last question (it was not still answered and none's effort was wasted) as I got back and thought to re-read JNI documentation, to find I misinterpreted some bits. Things are now clearer ...
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Obfuscated Config Files: EHI Files for HTTP Injector

So I have an ehi file, which is a configuration file for an Android App called HTTP Injector. Of course when I try to see it as a simple text, I just get random characters. What tool could I use to ...
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Calling functions of a shared object (.so) extracted from an APK

Decompiling a regular Android application I noticed that its code uses some native functions. So, unpacking the (.apk) file I found the usual "lib" folder and under that a series of folders for ...
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decompiled android application with only one class [DexProtector]

I'm trying to reverse engineering an android app and it's mostly for an experiment but I have a problem that I can't find a solution or even what is the problem. I decompiled an app with JADX-gui and ...
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Common practices for 'hiding' a class within an Android application?

I've recently gotten into Android reverse engineering, and I've been messing around with some apps lately for education/research purposes to see how some things are done with private (mobile) APIs. ...
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Intercept traffic from exe to my Java server

In Windows 10, I can easily intercept traffic of an application using Proxifier and route it to Charles proxy, so that I can inspect and edit the data. exe -> Proxifier (Socks proxy to localhost:...
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Is there any way to get value from bytecode under JDWP without access to source?

When I debug android app through jdwp using jdb, it seems I can't get anything from the bytecode level. I know normally it's fine as long as we have the source line info and use a decompiler, but the ...
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Java Bytecode edit

Hi, I would like to edit one compiled java class file & like to insert & edit a couple of lines. I'm trying to make a patch for a software & when I compare this two file the only change I ...
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rebuilding a java application

I wish to rebuild MotiveWave, a charting tool, from its jars. This application has a feature (probably in one of the class files but I don't know which) that i want to build upon. I mean I want to ...
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1 vote
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93 views

Accessing debug log on Java application

I'm currently reverse engineering a JSP applet running through JBoss. Decompiling the code it looks like there are a bunch of Logger.debug() calls in the code that aren't guarded. A quick read through ...
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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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  • 179
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1 answer
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Certain classes do not show up in JDB while they are present in source code

I'm debugging a closed-source Android app with jdb. In the output produced by the apktool, I see class com.myapp.j.d.d, as well as a/b/c/e, but at run-time, I see only com.myapp.j.d.e. Why is that ...
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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?
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68 views

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, ...
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<"..." is not a valid class name"> when trying to debug an android app using jdb

I am trying to reverse engineer an android app for education purpose, but I ran into an annoying problem: the android app is obfuscated and some classnames start with digits. So when I tried putting a ...
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Injecting class into the JNIEnv in android jni

void *handle = dlopen("/data/local/tmp/libnative-lib.so", RTLD_LAZY); if (!handle) { printf("\nFailed to load library\n"); } void *offset = dlsym(handle, "...
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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 ...
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Need help logging string in smali

I'm trying to log p1 string to logcat. This is my function. new-instance v4, Ljava/lang/StringBuilder; invoke-direct {v4}, Ljava/lang/StringBuilder;-><init>()V invoke-virtual {v4, v3}, ...
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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,...
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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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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 ...
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0 votes
1 answer
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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 ...
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104 views

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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2 answers
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Load Library Android

I work as cybersecurity consultant, and now I am on mission to reverse engineering of mobile app. I always reverse it using Jadx and dex2jar... the problem that after reverse them I found some native ...
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-1 votes
1 answer
138 views

decomplied apk with bad parameters

I'm trying to reverse engineering an android app API so this is what I tried: First the app was using Okhttp certificate pinning and I couldn't track the URLs with Charles then I tried this method ...
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-3 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?
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