YARA - a malware identification and classification tool

YARA is a tool aimed at helping malware researchers to identify and classify
malware samples. With YARA you can create descriptions of malware families
based on textual or binary patterns contained on samples of those families.
Each description consists of a set of strings and a Boolean expression which
determines its logic.

YARA 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.