unidbg is a Java-based emulator framework for Android native libraries with experimental iOS support. It provides JNI/VM emulation, hooks, various backends, memory leak detection, and MCP AI-assisted debugging features.
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What it is
Allows you to emulate an Android native library, and an experimental iOS emulation. This is an educational project to learn more about the ELF/MachO file format and ARM assembly.
How it works
Features include: MCP (Model Context Protocol) debugging integration, JNI_OnLoad emulation, JavaVM/JNIEnv emulation, syscall instruction emulation, ARM32/ARM64 support, inline hooks via Dobby, Android import hooks via xHook, iOS fishhook and Whale hooks, Unicorn backend with a console debugger and tracing, iOS objc/swift runtime, dynarmic backend, Apple M1 hypervisor backend, Linux KVM backend for Raspberry Pi B4, and memory leak detection with guest/backtrace reporting.
Getting started
The repository provides MCP quick start and tools to run custom MCP tools, attach a debugger, and start an MCP server for AI-assisted analysis. Examples show how to attach a debugger, set breakpoints, and run MCP tooling:
Debugger debugger = emulator.attach();
debugger.addBreakPoint(address);
McpToolkit toolkit = new McpToolkit();
toolkit.addTool(new McpTool() {
@Override public String name() { return "encrypt"; }
@Override public String description() { return "Run encryption"; }
@Override public String[] paramNames() { return new String[]{"input"}; }
@Override public void execute(String[] params) {
String input = params.length > 0 ? params[0] : "default";
// call encryption with input
}
});
toolkit.run(emulator.attach());
McpToolkit toolkit = new McpToolkit();
toolkit.addTool(new McpTool() {
@Override public String name() { return "dumpClass"; }
@Override public String description() { return "Dump an ObjC class definition by name"; }
@Override public String[] paramNames() { return new String[]{"className"}; }
@Override public void execute(String[] params) {
String className = params.length > 0 ? params[0] : "AppDelegate";
IClassDumper classDumper = ClassDumper.getInstance(emulator);
System.out.println("dumpClass(" + className + "):\n" + classDumper.dumpClass(className));
}
});
toolkit.run(emulator.attach());
Low-level API: Debugger.addMcpTool() + Debugger.run(DebugRunnable) for full control.
Recent releases
Latest releases include:
- v0.9.9 (2026-03-05)
- v0.9.8 (2024-09-05)
- v0.9.7 (2022-07-30)
- v0.9.6 (2022-01-31)
- v0.9.5 (2021-09-21)
Traction
Stars: 5105 Forks: 1170 Open issues: 419
License
Apache-2.0
What it does (concrete capabilities)
- Emulates Android native libraries and experimental iOS emulation.
- Supports MCP (Model Context Protocol) debugging for AI-assisted tooling.
- Emulates JNI Invocation API, JavaVM, and JNIEnv.
- Emulates syscalls and supports ARM32/ARM64 architectures.
- Inline hooking (Dobby) and Android import hooks (xHook).
- iOS hooks via fishhook, substrate, and whale; Unicorn backend with basic debugger and trace features.
- Backends for Apple M1 hypervisor and Linux KVM (Raspberry Pi B4).
- Memory leak detection with guest backtrace and host stack trace.
- Memory tracking usage example shown with MemoryTracker and try-with-resources.
Examples and tests
Examples mention tests under src/test and include utilities demonstrating JNI/dispatch, and memory leak checks.
Relationships
Unidbg is an educational project focusing on ELF/MachO formats and ARM assembly understanding, with APIs for emulation, debugging, and memory tracking.