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https://github.com/stoerchl/yara_zip_module


https://github.com/stoerchl/yara_zip_module

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# 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