Questions tagged [android]

Android is Google's Linux-based operating system for mobile devices. Initially developed by Android, Inc., Android is the world's most widely used smartphone platform.

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2answers
56 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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0answers
20 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
20 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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0answers
20 views

How to read dnSpy code from assembly_csharp.dll

So I have managed to retrieve the assembly_csharp.dll using the il2cpp tool from an android apk, however my issue is that when I go to read the dll using dnSpy I have all the correct looking function ...
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26 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 ...
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1answer
59 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 ...
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0answers
67 views

Unpack, modify and rebuild an Android App Bundles (.aab) file

I would like to unpack an .aab file, decompile/recompile the classes.dex (baksmali/smali), edit the manifest and, finally, generate a new .aab file. Basically, I am looking for an apktool for .aab
2
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1answer
33 views

apk crashed on launch when re-signed with debug key

I sometimes decompile and recompile apks and make changes (like changing graphics, text etc...) normally I use apktool to decompile and recompile and then use testsign.jar to resign the apk with the ...
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0answers
48 views

Protection of Financial Apps against repackaging

I have tried repackaging few financial apps and when I tried running their repackaged version, I found out that either it is getting crashed at the launcher activity, or at the later point it is ...
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0answers
29 views

How do I find the function that draws a window on android?

I have an application that recently disabled support for one of the features I used for legal reasons. Looking at the decompressed file size and count of the new version compared to the old version ...
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0answers
62 views

extracting png file from app

I have extracted some png files from one app. I cannot open them using android gallery neither on windows. Can you help understanding what is really this file and what should be changed in order to ...
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0answers
31 views

Android - capture screen with the lowest latency via android native code

I'm trying to catch small fragment of screen during working some Android app which I'm currently reversing. I've tried screencap with various calls but minimum latency which I was able to achieve was ...
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1answer
39 views

Understanding how a WiFi camera app goes from packet data to video stream

I have a WiFi webcam that I'm trying to get to stream to my computer. I'm able to get the camera to send data to my computer, but I don't know how to decode it. The data consists of 11 1450 byte ...
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49 views

Reverse an encryption algorithem in APK .so file

I try to reverse a cipher algorithm (I guess Tiny Encryption Algorithm (TEA)) in an android application. But I have a serious problem in initializing arguments. How I can understand that I have ...
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1answer
67 views

Is it possible to work around SQLcipher by modifying libsqlcipher.so?

I was trying to extract data from an Android app which uses SQLcipher. SQLcipher is an extension of SQLite that encrypts database files with 256-bit AES. Within the APK, the library lies in lib/...
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1answer
32 views

Any ways to combine Android APK with Expansion pack file?

I want to have only one APK that contains all files and resources without having to download expansion pack every time. Is there any way to combine Android APK with Expansion pack file? My expansion ...
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0answers
92 views

Decode lua scripts for cocos2d based game / frida, android

I'm trying to decrypt LUA scripts from cocos2dx game (for wiki). In most cases, it's XXTEA based, but not in this case. The game itself: https://apkpure.com/might-magic-era-of-chaos/com.ubisoft.might....
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0answers
63 views

capture traffic of an android app

I was trying to test and intercept traffic from an app developed on Rhodes open source framework, I setup a proxy with burp, and of course I have installed burp certificate on my device hence I can ...
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1answer
83 views

Can't CVE-2019-2215 on Android: “Unable to handle kernel paging request at virtual address”

I'm playing with Android and I'm trying to gain r/w access to the whole memory using CVE-2019-2215. Long story short, you UAF a binder_thread object and you can read from/write to kernel space. The ...
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0answers
44 views

How to get pointer's address?

I've tried to reverse engineering Clash Royale. First strange thing is that I can't find libg.so in maps. cat /proc/<pid>/maps | grep libg.so As I understand split_config.arm64_v8a.apk contains ...
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0answers
51 views

Frida not able to trace sub_XXXXX which must have been called

I have the following pseudocode generated by IDA Pro decompiler: __int64 *__usercall sub_155B5@<X0>(__int64 *a1@<X0>, unsigned int a2@<W1>, char **a3@<X8>) { ... result = ...
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0answers
22 views

change apk versionName not working

I am reverse engineering an apk. after decompiling apk file when i try to change versionName from AndroidManifest.xml 3.4 to 5.7, it working well, but when i try to change 3.4 to 5.7.1 or 3.4.1.2 apk ...
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1answer
169 views

hooking libhoudini on x86 emulator

I'm trying to hook libhoudini to debug an application instruction by instruction using frida but frida not supports it i need a example on how can this be achieved! I'm using a x86 emulator to run arm ...
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0answers
169 views

Instruction trace using frida in android emulator

i have a emulator named "Ldplayer" in my windows os and I'm trying to log all instructions executed by the app that uses ARM JNI libraries. basically, the app is running in an x86 emulator ...
2
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1answer
101 views

Getting android app from device for reversing - what if there are multiple apks?

For analyzing and reversing android apps, where the target app is installed on an android phone, usually there is a base.apk file on the device, and there are various ways to find this apk file on the ...
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1answer
48 views

Call of a suspicious method cannot be found

i have a strange apk which I took a closer look at, among others with jadx-gui. It is a gaming app that requires an unusual amount of permissions according to the manifest file. I installed and played ...
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1answer
134 views

How to reverse engineer apks? [closed]

is it possible to reverse engineer an apk just to unlock hidden/unreleased features?
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1answer
88 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 ...
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1answer
93 views

Modifying (adding new logic) decompiled apk to log different kind of data causing problems (crash/bluetooth connection)

I have separately decompiled apk to smali/dalvik and to java classes. As apk is not obfuscated java code is pretty good to read and I can pretty easily see corresponding smali code. So far I was able ...
2
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1answer
184 views

how to decompile or unite multipart dex class in an android apk file?

Some Android Apks contain multiple classes.dex files which are numbered like this: classes1.dex, classes2.dex ... and when i try to decompile them it would result into multiple source codes. Is there ...
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1answer
135 views

IDA Pro: How to change segment register value

For a specific Android library that I have loaded into IDA, I want to switch the THUMB/ARM mode to ARM, no matter the consequences that this is going to have to the code. Is there a way to efficiently ...
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1answer
42 views

methods that have zero usage in jadx?

so i've been reversing this ai assistant app to figure out what kind of forensic data it leaves on local file system. during static analysis with jadx-gui i found some interesting methods that take ...
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1answer
148 views

Android packageInfo signature

Are there anyways I can learn what packageInfo.signatures[0] is so I can use it to apply the same algorithm in Python. To further explain: private static SecretKeySpec a(Context context) { ...
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1answer
87 views

App from playstore runs but the same apk crashes on sideload install

On my nougat device, I have downloaded an app from the playstore, which is running great. I then extract the apk from the installed app, and uninstall it and again successfully, with package installer....
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1answer
149 views

Read bytearray from retval on onLeave event

I'm trying to get the return value of a android native function call using Frida but with no success: Interceptor.attach(Module.getExportByName('lib.so', 'Token'), { onEnter: function(args) { ...
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1answer
42 views

how to replace the result from a json request into a variable [closed]

I would like to return in v0 the following answer "FR" instead of the country retrieved from Json .method public getCountryCode()Ljava/lang/String; .registers 2 .line 11 iget-object v0, p0, ...
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1answer
728 views

Change androidmanifest.xml file within apk

I am able to unpack an android apk file with apktool, but when I am repacking the apk file using apktool, it just crashes with errors, and ibotpeaches seems not patching those errors for years. Now ...
1
vote
1answer
92 views

Charles TLS Proxy for Android device with root access

I am trying to setup a TLS proxy with Charles proxy to man-in-the-middle an Android app. I would like to be able to view the contents of HTTPS traffic. This is not an app that I built, rather I am ...
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0answers
56 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 ...
2
votes
1answer
157 views

Invalid file path error while trying to rebuild with apktool and aapt2

I am facing an error while try to repack an apk with apkool. below is the error trace. W: error: invalid file path 'C:\Users\ccre\res\drawable2\abc_ic_search_api_material.xml'. W: error: invalid file ...
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0answers
24 views

compile gdb with python 3 for gef-ida-interact

I'm trying to use GEF's IDA-interact which has issues with python2. I'm using android-ndk-r20b/prebuilt/linux-x86_64/bin/gdb - v7.11 using Python engine 2.7 How do I compile gdb with python 3.x ? I ...
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0answers
300 views

Endoscope Camera YPC99 - how to stream on linux

I'm trying to stream video from endoscope camera YPC99 on linux PC using the WiFi connection. From what I have found so far the camera is using IP 192.168.1.1. It supports RTSP protocol on port 7070 (...
3
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1answer
175 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 ...
1
vote
1answer
190 views

Unable to intercept traffic of an android app even after patching ssl pinning

Recently, I was trying to test an app developed on Rhomobile, I setup a proxy with burp, and of course I have installed burp certificate on my device hence I can intercept other apps on my device but ...
0
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0answers
59 views

What is the approach to find apps(Android) to reverse engineer?

How does one "choose" an app to do reverse engineering/analysis on (say finding bugs or malicious behavior) About me: I'm a beginner at Android App RE, have used various tools to solve some CTF apps ...
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0answers
271 views

Frida finding out a decryption/decode algorithm

It's been a few days I'm working on an application to find out about an encryption it is using on a few strings received from API, but no success so far. These are the strings: ...
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0answers
28 views

can't see java file but debugger shows it is present and can access using reflection

I am debugging an android application to find out the implementation of something. I am using a debugger in Android studio from which I came to know that there is a java file that is responsible but ...
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1answer
35 views

How do I know which class/file in apk is being used for what purpose?

I am new to this sort of stuff. I just found hardcoded public and private keys in an android app. I just can't figure out what it is being used for. Any advice on that?
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1answer
135 views

Proper way of implementing DexGuard RASP device checks

I recently came across an app that is protected with DexGuard. DexGuard claims to offer Runtime Application Self Protection (RASP), which comprises of app obfuscation and various runtime tampering ...
2
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1answer
51 views

What code gets executed in an ELF binary when Java loadLibrary() is called

I’ve been working on reverse engineering this android x86 ELF binary. According to my research when loadLibrary() is called the function JNI_onLoad is supposed to be executed however this binary doesn’...

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