evilfonttool 2.0.0

Evil Font steganography tool for security research

EvilFontTool

A font-based deception tool for red teaming, security research, and whatever else.

EvilFontTool hides machine-readable text inside a document that displays completely different text to a human reader. It does this using Evil Fonts — fonts that intentionally deceive the viewer by rendering a different letter than understood by a computer. By remapping font glyphs, the document's visible characters show humans one thing while terminals, AI systems, and clipboard copy paste see another.

Evil Font Demo !!DON'T MISS THIS!!

View the Demo → Here (hosted on GitHub Pages)

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Table of Contents

• Installation
• Usage
• Ethical Use & Disclaimer
• Contributing

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How It Works — Blog Post Coming Soon

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Installation

git clone https://github.com/DoctorEww/EvilFontTool.git
cd EvilFontTool
pip install .

For development (editable install):

pip install -e .

Dependencies

• fonttools — font parsing and manipulation
• python-docx — DOCX generation

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Where can I find fonts to use?

• Ubuntu: /usr/share/fonts
• Windows: C:\Windows\Fonts
• https://fonts.google.com/
• The internet??

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Usage

All functionality is exposed via a single CLI with three subcommands.

create — Generate the font family for use in HTML or DOC files

evilfonttool create <reference_font> <output_dir> <font_name>

Argument	Description
reference_font	Path to a .ttf or .woff source font
output_dir	Directory to write fonts and CSS into
font_name	Internal name prefix for the generated font family

Example:

evilfonttool create fonts/Arial.ttf output/ 'Arial'

Outputs:

• output/fonts/*.woff — web fonts, one per character
• output/ttffonts/*.ttf — TTF fonts for document embedding
• output/fonts.css — @font-face declarations for web use

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web — Generate an evil font HTML file

evilfonttool web <human_file> <computer_file> <output_file>

Requires fonts.css and the generated fonts to be in the output directory so the HTML file can use it (or change the path in the HTML file).

Example:

evilfonttool web human.txt computer.txt output/index.html

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doc — Generate a evil font DOCX file

evilfonttool doc <human_file> <computer_file> <output_file> <font_name>

The font_name must match the name used in the create step. The TTF fonts must be installed on the system or embedded in the document. When saving the doc file you can choose in the file -> options -> save to embed the fonts in the file so its portable.

Example:

evilfonttool doc human.txt computer.txt output/secret.docx MyFont

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Input File Format

• Plain .txt files, one sentence or phrase per line
• Each line in computer_file must be equal to or longer than the corresponding line in human_file
• Lines are matched positionally (line 1 to line 1, etc.)

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Ethical Use & Disclaimer

You are responsible for how you use this tool. Deploying this technique against systems or individuals without explicit authorization is unethical and may be illegal. The authors provide this tool to help defenders understand and test for this class of vulnerability — not to enable attacks.

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Contributing

Contributions are welcome. If you've found a new attack surface, an improvement to the font generation pipeline, or a defense technique worth documenting, please open an issue or PR.

1. Fork the repo
2. Create a feature branch (git checkout -b feature/my-feature)
3. Commit your changes
4. Open a pull request with a clear description of what changed and why