I'm trying to extract the relevant symbols from a shared library that contains JNI glue code, but nm doesn't seem to help enough. The method signatures aren't there so I don't know which arguments to pass.
Android NDK Libraries Signatures
Download Zip: https://imepxtahi.blogspot.com/?file=2vAiS8
Android applications can contain compiled, native libraries. Native libraries are code that the developer wrote and then compiled for a specific computer architecture. Most often, this means code that is written in C or C++. The benign, or legitimate, reasons a developer may do this is for mathematically intensive or time sensitive operations, such as graphics libraries. Malware developers have begun moving to native code because reverse engineering compiled binaries tends to be a less common skillset than analyzing DEX bytecode. This is largely due to DEX bytecode can be decompiled to Java whereas native, compiled code, often must be analyzed as assembly.
Object Libraries under Xcode have special handling ifmultiple architectures are listed in CMAKE_OSX_ARCHITECTURES.In this case they will be exported as Interface Libraries withno object files available to clients. This is sufficient to satisfytransitive usage requirements of other targets that link to theobject libraries in their implementation.
This signature exports cmake built targets to the android ndk build systemby creating an Android.mk file that references the prebuilt targets. TheAndroid NDK supports the use of prebuilt libraries, both static and shared.This allows cmake to build the libraries of a project and make them availableto an ndk build system complete with transitive dependencies, include flagsand defines required to use the libraries. The signature takes a list oftargets and puts them in the Android.mk file specified by the given. This signature can only be used if policyCMP0022 is NEW for all targets given. A error will be issued ifthat policy is set to OLD for one of the targets.
Notes: If you encounter "java.lang.UnsatisfiedLinkError: hello.dll: Can't find dependent libraries", you need to find a "DLL dependency walker" to track down the dependent libraries. Search for the libraries (under Cygwin) and include the libraries in the environment variable PATH. In my case, the dependent library is "libstdc++-6.dll" located at "cygwin64\usr\x86_64-w64-mingw32\sys-root\mingw\bin".
Notes: If you encounter "java.lang.UnsatisfiedLinkError: hello.dll: Can't find dependent libraries", you need to find a DLL dependency walker to track down the dependent libraries. Search for the libraries (under Cygwin) and include the libraries in the PATH. In my case, the dependent library is "libstdc++-6.dll" located at "cygwin64\usr\x86_64-w64-mingw32\sys-root\mingw\bin".
Updated internal Crashpad version to commit 281ba7. With thischange, disabling tagged pointers is no longer required, so the following canbe removed from your manifest's application tag:android:allowNativeHeapPointerTagging=false.
This SDK now requires devices and emulators to target API level19 (KitKat) or higher and to use Android 4.4 or higher. This is due to anupdate in its gRPC dependency version and to align with requirements of otherFirebase libraries.
Modified the Breakpad symbol generator binary to be globallyexecutable and to statically link against standard libraries, which shouldresolve build errors for NDK developers using Docker-based CI systems.
To continue using Google AdMob, you need to explicitly add the dependency for the Google Mobile Ads SDK including its version (com.google.android.gms:play-services-ads:21.5.0) to your app's build.gradle file.
We'll have these issues fixed in the near future. Until then, here are a few self-serve fixes that involve including an additional library into your build based on the ML library that you're using. If you're using more than one of these faulty libraries, make sure to include each corresponding fix.
This requires extracting and adding (upstream) developer signatures tofdroiddata. These signatures are then later copied to the unsigned APKbuilt from the fdroiddata recipe. We provide a command for easilyextracting signatures from APKs:
F-Droid verifies reproducible builds using the APKsignature (aform of embeddedsignature),which requires copying thesignature from a signed APK to an unsigned one and then checking if thelatter verifies. The old v1 (JAR) signatures only cover the contents ofthe APK (e.g. ZIP metadata and ordering are irrelevant), but v2/v3signatures cover all other bytes in the APK. Thus, the APKs must becompletely identical before and after signing (apart from the signature)in order to verify correctly.
Embedded build paths area source of reproducibility issues affecting apps built with e.g. Flutter,python-for-android, or using native code (e.g. Rust, C/C++, any kind oflibfoo.so). Apps completely written in Java and/or Kotlin tend to beunaffected.
It seems that the stripping of native libraries, e.g. libfoo.so, can causeintermittent reproducibility issues. It is important to use the exact NDKversion when rebuilding, e.g. r21e. Disabling stripping can sometimeshelp. Gradle seems to strip shared libraries by default, even the app isreceiving the shared libraries via an AAR library. Here is how to disableit in Gradle:
One possible solution is adding -Wl,--build-id=none to link options whichwill disable build-id generation completely. For ndk-build, LOCAL_LDFLAGS += -Wl,--build-id=nonecan be added to Android.mk files. For cmake versions since 3.13, add_link_options(-Wl,--build-id=none)can be added to CMakeLists.txt globally. For cmake versions before 3.13,target_link_libraries( -Wl,--build-id=none) can be used instead forevery target.
ionic-framework cordova angularjs android ios mobile Use the Apache Cordova File plugin with Ionic Framework to create a file browser for Android and iOS. Navigate directories in your device storage and find the files you're looking for using simple AngularJS.
ionic angularjs cordova android ios phonegap A year feedback on Ionic Framework THE open source front-end SDK for developing hybrid mobile apps. This post is about what we love about Ionic (UI, Build, Debug, Performance) and what we learnt (limitations) throughout our journey.
ASignature is a library for drawing smooth signatures. It uses variable width Bézier curve interpolation based on Smoother Signatures. It works from API 8+ and doesn't depend on any external libraries.
Abstract Introduction Introduction to the Java Native Interface (JNI) Characteristics of the anti-analysis library Naming Variants Key signatures of the ELF Analysing the library In-place decryption Generating the seed arrays Decryption algorithm Decrypted contents Run-time environment checks System properties checks Verifying CPU architecture Identifying if Monkey is running Current process not hooked with Xposed Framework Conclusion References Appendix: IDAPython decryption script
Malware authors implement many different techniques to frustrate analysis and make reverse engineering malware more difficult. Many of these anti-analysis and anti-reverse engineering techniques attempt to send a reverse engineer down a different investigation path or require them to invest large amounts of time reversing simple code. This talk analyses one of the most interesting anti-analysis native libraries we've seen in the Android ecosystem. No previous references to this library have been found. We've named this anti-analysis library 'WeddingCake' because it has lots of layers.
The sample Android application includes a native library to hide the contents and functionality of native code. The Java Native Interface (JNI) allows developers to define Java native methods that run in other languages, such as C or C++, in the application. This allows bytecode and native code to interface with each other. In Android, the Native Development Kit (NDK) is a toolset that permits developers to write C and C++ code for their Android apps [2]. Using the NDK, Android developers can include native shared libraries in their Android applications. These native shared libraries are .so files, a shared object library in the ELF format. In this paper, the terms 'native library', 'ELF', and '.so file' are used interchangeably to refer to the anti-analysis library. The anti-analysis library that is detailed in this paper is one of these Android native shared libraries.
In order to run a native method from Java, the native method must be 'registered', meaning that the JNI knows how to pair the Java method definition with the correct function in the native library. This can be done either by leveraging the RegisterNatives JNI function or through 'discovery' based on the function names and function signatures matching in both Java and the .so [4]. For either method, a string of the Java method name is required for the JNI to know which native function to call.
After the CPU architecture check, the library attempts to iterate through every PID directory under /proc/ to determine if com.android.commands.monkey is running [6]. The code does this by opening the /proc/ directory and iterating through each entry in the directory, completing the following steps. If any step fails, execution moves to the next entry in the directory.
In order to determine if Xposed is running, the library, checks if 'LIBXPOSED_ART.SO' or 'XPOSEDBRIDGE.JAR' exist in /proc/self/maps. If either of them exist, then the application exits. /proc/self/maps lists all of the memory pages mapped into the process memory. Therefore, you can see any libraries loaded by the process by reading its contents.
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 largely constitues learning by myself but I really don't know what to look or where to look. Some examples would be really helpful. Thanks! 2ff7e9595c
Commentaires