Commonly referred to as “Shared Object rules”, “SO rules”, “pre-compiled rules”, or “Shared Objects” are detection that is written in the Shared Object rule language, which is, essentially, “C”. This allows for primarily two things for the Snort platform:
Talos distributes shared object rules on a variety of platforms, easy to install and use.
However, some may be finding it difficult to use the rules, so let me point you to a couple guides. Talos has a blog post that can help you install the Shared Object rules.
But, by far, the easiest way to use Shared Object rules reliably is through the configuration and use of a tool called PulledPork. After the configuration of PulledPork, the tool will generate the Shared Object rule stubs for you, and place everything in the correct directories for ease of use. This is amongst the many features of PulledPork (including flowbit dependency resolving) which are useful.