YARA v4.4 releases: The pattern matching swiss knife

YARA is a tool aimed at (but not limited to) helping malware researchers to identify and classify malware samples. With YARA you can create descriptions of malware families (or whatever you want to describe) based on textual or binary patterns. Each description, a.k.a rule, consists of a set of strings and a boolean expression that determine its logic. Let’s see an example:

rule silent_banker : banker

{

    meta:

        description = "This is just an example"

        threat_level = 3

        in_the_wild = true



    strings:

        $a = {6A 40 68 00 30 00 00 6A 14 8D 91}

        $b = {8D 4D B0 2B C1 83 C0 27 99 6A 4E 59 F7 F9}

        $c = "UVODFRYSIHLNWPEJXQZAKCBGMT"



    condition:

        $a or $b or $c

}

The above rule is telling YARA that any file containing one of the three strings must be reported as silent_banker. This is just a simple example, more complex and powerful rules can be created by using wild-cards, case-insensitive strings, regular expressions, special operators and many other features that you’ll find explained in YARA’s documentation.

It is multi-platform, running on Windows, Linux, and Mac OS X, and can be used through its command-line interface or from your own Python scripts with the Yara-python extension.

If you plan to use YARA to scan compressed files (.zip, .tar, etc) you should take a look at yextend, a very helpful extension to YARA developed and open-sourced by Bayshore Networks.

Changelog v4.4

• fix: If any signature is valid, the file is properly signed (#1936)

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Copyright (c) 2007-2016. The YARA Authors. All Rights Reserved.

Christian Blichmann <cblichmann@google.com>
Hilko Bengen <bengen@hilluzination.de>
Joachim Metz <joachim.metz@gmail.com>
Karl Hiramoto <karl.hiramoto@virustotal.com>
Mike Wiacek <mjwiacek@google.com>
Shane Huntley <shuntley@google.com>
Stefan Buehlmann <stefan.buehlmann@joebox.org>
Victor M. Alvarez <plusvic@gmail.com>;<vmalvarez@virustotal.com>
Wesley Shields <wxs@atarininja.org>