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.
152
questions
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40 views
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
...
2
votes
3answers
318 views
Secure resources from being extracted?
I have a jar file with a resources folder, and I have converted it to EXE using Launch4J.
How can I protect my resources from being extracted using winzip/winrar ?
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1answer
73 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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2answers
1k views
What functions (in which modules) can be hooked by Frida to access unencrypted data of SSL connections in Java programs running under Windows?
There are gazillions of internet resources discussing how to use Frida to hook and otherwise mess around with SSL connections of Java programs running under Android, but seemingly (as far as my google-...
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1answer
213 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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0answers
38 views
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}, ...
1
vote
0answers
33 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
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1answer
72 views
Java Help Understanding RSA Encrypt/Decrypt file and SD card
I was directed tyhis way from the main superuser site:
I have zero experience with Java or Android apps (have coding experience in C) and tried reverse engineering a [now defunct/unsupported] app ...
0
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2answers
111 views
Load Library Android
I Work as cybersecurity consultant and now i'am in 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 ...
5
votes
1answer
497 views
Reverse engineering android native packer
im trying to Reverse engineering an android app and the app have 4 folders in the /data/data/{package} folder
├───app_dexprotector
│ 823517D25836B88F1C499C02370A047E.dat
│ ...
2
votes
1answer
133 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 ...
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0answers
37 views
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
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0answers
86 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 ...
-1
votes
1answer
104 views
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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0answers
87 views
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 ...
3
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1answer
97 views
DEX file referenced type is not defined in file
I am analyzing a dex file and to ease with reverse engineering, I converted it a jar so it could be decompiled. In the file android/support/v17/leanback/media/MediaControllerGlue.class, the following ...
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0answers
27 views
Java Software cleanroom implementation
I'm trying to make a cleanrooom implementation of a java written lib. What resources can I use for it. Only the official software docs? Or can I use what I get after i throw the lib into a java ide (...
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0answers
116 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 ...
1
vote
1answer
380 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 ...
0
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0answers
21 views
"strings" command from *nix, but as a Java API?
Looking for the "strings" command from *nix, but as a Java API. Does such a library or JAR exist? I've automated calling the strings *nix command, but would like to explore reverse ...
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0answers
21 views
How can I find the native functions used by the Java Runtime Environment on Linux?
I am not usually a Java programmer, but I need to locate for example, which native functions (or APIs) are used in something like java.io.File.createNewFile() on Linux?
Initially, I am thinking of 2 ...
3
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2answers
335 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....
1
vote
0answers
479 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 ...
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82 views
App crashes upon launch after apktool d, apktool b without changing anything
I would like to modify some codes via apktool.
However it crashes once I signed it and installed it.
I have tried resigned it without using apktool.
It works. So I am pretty sure that the app does ...
1
vote
1answer
99 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 ...
1
vote
2answers
245 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 ...
1
vote
2answers
6k views
How to add code to compiled java class
I have java code that is compiled to a .class file.
There is a function that gets few parameters and do some action (e.g. get int x and int y and do x+y)
I want to add to this .class file code that ...
1
vote
1answer
429 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 ...
0
votes
1answer
633 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
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2answers
2k views
Java - Decipher encrypted classes in a jar file
I have a couple of classes that are encrypted. The class loader must decrypt these before executing in the JVM.
The question is, how and where?
What can I do to understand who is responsible to ...
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1answer
184 views
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 &...
2
votes
1answer
585 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 ...
3
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0answers
30 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 ...
1
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1answer
92 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
...
55
votes
7answers
121k views
What is a good Java decompiler and deobfuscator?
I am using JD-GUI to decompile Java JAR files, but the problem is that it leaves many errors, such as duplicate variables which I have to fix myself and check to see if the program still works (if I ...
2
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0answers
139 views
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 ...
6
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2answers
2k views
Trace system calls, including stack (and java stack if possible), on android?
I have an android app that reads/writes a data file which seems to be encrypted, and i want to make a tool to read/write that file, so i need to reverse the encryption.
The app in question consists ...
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votes
1answer
607 views
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?
7
votes
2answers
6k views
Hooking Java APIs
In native code on windows functions can be hooked by replacing their prologue with a JMP instruction.
Is there a way to do something similar with an application written in java? In the end I want to ...
2
votes
1answer
312 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
1answer
305 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 ...
1
vote
2answers
294 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 ...
1
vote
1answer
352 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 "...
0
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0answers
80 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-...
1
vote
1answer
229 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
...
3
votes
1answer
234 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 ...
3
votes
1answer
276 views
What is the problem with using inner classes in a class enclosing sensitive information?
I recently heard that using Java inner classes in a class that enclose sensitive information is causing the private data of the class to be changed to protected at the bytecode level (meaning that any ...
1
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0answers
98 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 ...
5
votes
1answer
3k views
How to do debug a running java process in linux?
TLDR I want to do live debugging of a java program on a linux machine, and don't how/what debugger to attach to the JVM to get this done.
I expect that this is a well-solved problem, but I lack the ...
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0answers
332 views
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
...
