pySigma 0.4.0

Sigma rule processing and conversion tools

pySigma

pySigma is a python library that parses and converts Sigma rules into queries. It is a replacement for the legacy Sigma toolchain (sigmac) with a much cleaner design and is almost fully tested. Backends for support of conversion into query languages and processing pipelines for transforming rule for log data models are separated into dedicated projects to keep pySigma itself slim and vendor-agnostic. See the Related Projects section below to get an overview.

Getting Started

To start using pySigma, install it using your python package manager of choice. Examples:

pip install pysigma
pipenv install pysigma
poetry add pysigma

Documentation with some usage examples can be found here.

Features

pySigma brings a number of additional features compared to sigmac, as well as some changes.

Modifier comparison between pySigma and sigmac

Modifier	Use	sigmac legacy
contains	the value is matched anywhere in the field (strings and regular expressions)	X
startswith	The value is expected at the beginning of the field's content (strings and regular expressions)	X
endswith	The value is expected at the end of the field's content (strings and regular expressions)	X
base64	The value is encoded with Base64	X
base64offset	If a value might appear somewhere in a base64-encoded value the representation might change depending on the position in the overall value	X
wide	transforms value to UTF16-LE encoding	X
re	value is handled as regular expression by backends	X
cidr	value is handled as a IP CIDR by backends
all	This modifier changes OR logic to AND	X
lt	Field is less than the value
lte	Field is less or egal than the value
gt	Field is Greater than the value
gte	Field is Greater or egal than the value
expand	Modifier for expansion of placeholders in values. It replaces placeholder strings (%something%)

Overview

Conversion Overview

Pipelines

More details are described in the documentation.

Testing

pySigma uses pytest as testing framework. Simply run pytest to run all tests. Run pytest --cov=sigma to get a coverage report.

Building

To build your own package run poetry build.

Contributing

Pull requests are welcome. Please feel free to lodge any issues/PRs as discussion points.

Maintainers

The project is currently maintained by:

• Thomas Patzke [e-mail]
• frack113

Related Projects

pySigma isn't a monolithic library attempting to support everything but the core. Support for target query languages and log data models is provided by additional packages that extend pySigma:

• sigma-cli: a command line interface for conversion of Sigma rules based on pySigma. (work in progress, not yet on PyPI)
• pySigma-backend-splunk:
• pySigma-pipeline-sysmon
• pySigma-pipeline-crowdstrike

All packages can also be installed from PyPI if not mentioned otherwise by the Python package manager of your choice.

License

GNU Lesser General Public License v2.1. For details, please see the full license file located here.