https://github.com/stoerchl/yara_zip_module

https://github.com/stoerchl/yara_zip_module

Last synced: 3 months ago
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• Host: GitHub
• URL: https://github.com/stoerchl/yara_zip_module
• Owner: stoerchl
• Created: 2018-11-05T20:56:17.000Z (about 6 years ago)
• Default Branch: master
• Last Pushed: 2022-10-21T12:23:53.000Z (about 2 years ago)
• Last Synced: 2024-04-19T18:32:48.994Z (7 months ago)
• Language: C
• Size: 83 KB
• Stars: 12
• Watchers: 2
• Forks: 2
• Open Issues: 1
• Metadata Files:
  • Readme: README.md

Awesome Lists containing this project

• awesome-yara - yara_zip_module

README

        
# yara_zip_module

This yara module can be used to search for strings inside a zip (.docx word file format) file. The files inside a zip are compressed and therefore not very well searchable for strings. This yara module unzips a requested file in memory and searches for a given string.

## Installation

The installation of the module should be pretty simple, but yara has to be built from source..

1. Clone the yara repository (https://github.com/VirusTotal/yara)

2. Copy yara_zip_modules files into the libyara folder of the yara clone:

```

	yara_zip_module/miniz.c --> yara/libyara/miniz.c

	

	yara_zip_module/include/yara/miniz.h --> yara/libyara/include/yara/miniz.h

	yara_zip_module/modules/zip.c --> yara/libyara/modules/zip.c

```

3. Edit the file yara/libyara/Makefile.am and add the module as well as the miniz library:

```

	MODULES += modules/zip.c

	yarainclude_HEADERS = include/yara/miniz.h

	

	libyara_la_SOURCES = miniz.c

```	

4. Add the module to the module_list file in the modules folder:

```	

	MODULE(zip)

```	

5. Now you can build yara by executing the make command inside the root folder.

More information can be found here: https://yara.readthedocs.io/en/v3.7.0/writingmodules.html

## Usage

The yara zip module has at the moment only one function `has_string(, )`

Following an example of a yara rule using the `has_string(..)` function.

If the given string was found, then the return value of the `has_string` function equals the offset inside the requested file.

	import "zip"

	rule embedded_html

	{

	    meta:

	    author = "@stoerchl"

	    info = "searches for a given string inside a zip file"

      

	    condition:

	        zip.has_string("word/document.xml", "wp15:webVideoPr") > 0

	}

## Thanks to

This module would not be working without this data compression library:

https://github.com/richgel999/miniz/

And without the yara project there obviously would have been no new yara module ;-)

https://github.com/VirusTotal/yara