sysnc - System Shell Netcat Command Sender

A utility for system shell command execution via netcat, exploiting Android zygote injection for operation. Primarily designed to run in Termux on Android devices.

Overview

sysnc is a bash wrapper around netcat that simplifies remote command execution and interactive shell access. It exploits Android zygote injection (CVE-2024-31317) for system shell.

Features

• Interactive Mode: Establish persistent netcat connections for interactive shell access
• Command Execution: Send single commands to remote servers and close connections
• Pipe Support: Execute piped shell script on the server

Installation

Quick Installation (Recommended)

1. Clone or download the script:

   git clone <repository-url>
   cd sysnc

2. Run the installation script:

   chmod +x install.sh
   ./install.sh

3. Restart your shell:

   source ~/.bashrc
   # or simply restart Termux

Manual Installation

1. Clone or download the script:

   git clone <repository-url>
   cd sysnc

2. Make the script executable:

   chmod +x sysnc

3. Install dependencies:

   # Update package list
   pkg update
   
   # Install netcat
   pkg install netcat-openbsd

4. Add to PATH:

   # Copy to system bin directory
   cp sysnc $PREFIX/bin/
   
   # Or add current directory to PATH
   echo 'export PATH=$PATH:$(pwd)' >> ~/.bashrc
   source ~/.bashrc

Verification

After installation, verify everything works:

# Check if sysnc is available
which sysnc

# Test help command
sysnc --help

Usage

Basic Usage

# Interactive mode (default)
sysnc

# Send a single command
sysnc -c "ls -la"

# Execute piped input
cat script.sh | sysnc

# Setup system shell netcat server
sysnc -s

# Show help
sysnc -h

Command Line Options

Option	Description
-c, --command	Send command to server and close connection
-s, --setup	Setup system shell netcat server
-h, --help	Show help message
(no args)	Interactive connection to server

Configuration

The script uses the following default configuration:

NC_HOST="localhost"
NC_PORT="1234"

To modify these settings, edit the script directly or set environment variables.

Android Zygote Injection Exploitation

This tool exploits Android zygote injection (CVE-2024-31317) to function. The -s option sets up the required netcat server using this exploitation technique.

Prerequisites

1. Shizuku and rish: Install Shizuku and setup rish with Shizuku for adb shell access, or run commands manually with adb

Setup Process

The -s option performs:

1. Stops the Android Settings app
2. Executes zygote injection with system UID 1000
3. Restarts the Settings app
4. Cleans up hidden API exemptions

Contributing

Contributions welcome. Submit issues, feature requests, or pull requests.

License

Educational purposes only. Use responsibly and in accordance with applicable laws.

Disclaimer

This tool is for educational purposes only. I am not responsible for any misuse of this software. Users must have proper authorization before running these commands.

References

• Android Zygote Injection CVE-2024-31317
• Shizuku Project
• Python-zygote-injection-toolkit