The ModSecurity-nginx connector is the connection point between nginx and libmodsecurity (ModSecurity v3). Said another way, this project provides a communication channel between nginx and libmodsecurity. This connector is required to use LibModSecurity with nginx.

The ModSecurity-nginx connector takes the form of an nginx module. The module simply serves as a layer of communication between nginx and ModSecurity.

Notice that this project depends on libmodsecurity rather than ModSecurity (version 2.9 or less).

What is the difference between this project and the old ModSecurity add-on for nginx?

The old version uses ModSecurity standalone, which is a wrapper for Apache internals to link ModSecurity to nginx. This current version is closer to nginx, consuming the new libmodsecurity which is no longer dependent on Apache. As a result, this current version has less dependencies, fewer bugs, and is faster. In addition, some new functionality is also provided - such as the possibility of use of global rules configuration with per directory/location customizations (e.g. SecRuleRemoveById).

Compilation

Before compile this software make sure that you have libmodsecurity installed. You can download it from the ModSecurity git repository. For information pertaining to the compilation and installation of libmodsecurity please consult the documentation provided along with it.

With libmodsecurity installed, you can proceed with the installation of the ModSecurity-nginx connector, which follows the nginx third-party module installation procedure. From the nginx source directory:

./configure --add-module=/path/to/ModSecurity-nginx

Or, to build a dynamic module:

./configure --add-dynamic-module=/path/to/ModSecurity-nginx --with-compat

Note that when building a dynamic module, your nginx source version needs to match the version of nginx you're compiling this for.

Further information about nginx third-party add-ons support are available here: http://wiki.nginx.org/3rdPartyModules

Usage

ModSecurity for nginx extends your nginx configuration directives. It adds four new directives and they are: