Detection Rule License (DRL)

The DRL 1.1, published by the Sigma project, is a permissive licence designed for detection content such as YARA and Sigma rules. It allows use, modification and redistribution, commercial included, provided you keep the author attribution, a link to the rule set and an indication of the licence — and that messages based on rule matches keep the author.

Signature Base and SEKOIA publish their rules under it. See public rule sets and the sources page.