ModSecurity is an open source product licensed under GPLv2 with a licensing exception (as of version 2.5.6) for linking and distribution with other Free/Libre and Open Source Software. It comes with full source code and documentation. Older releases are signed by Ivan Ristic. Newer releases are signed by Brian Rectanus. These public keys are available via most PGP key server mirrors.
Community-Produced Binary packages
There are no binary packages on modsecurity.org. Below is a list of third-party sites that sometimes have an up-to-date binary version of ModSecurity: