What is mkyar?

I was looking for awhile for a simple tool that can create Yara rules that can match binary files. I didn't find such tool so I made this one.

.. but why?

There are many use cases that such tool can enable:

• tamper-proof check of consistency of files
• detect library uses within binaries
• have fun with Yara :)

How to install

go install github.com/zinderic/mkyar@latest

How to use:

$ mkyar
Usage: mkyar <elf_file>
$

This runs the tool to generate test.yar file of gping and then runs the yara compiler to execute the rule.

$ go run . ~/Downloads/gping > test.yar && yara test.yar ~/Downloads/gping && rm test.
test_name /Users/zinderic/Downloads/gping
$

As we can see the rule did match the binary so we successfully and automatically created Yara rule for the file.

Tip: you'll need the Yara compiler or something that can run the rule. The yara command in the above example is the Yara compiler.

The gping binary file can be any elf (Linux) binary. I used this one in the example - https://github.com/orf/gping/releases/download/gping-v1.12.0/gping-Linux-x86_64.tar.gz. Just make sure to extract the actual binary.

Future work:

• Add support for MacOS binaries (Mach-O)
• Add support for Windows binaries (PE)