NAXSI means Nginx Anti XSS & SQL Injection.
Technically, it is a third party nginx module, available as a package for
many UNIX-like platforms. This module, by default, reads a small subset of
simple (and readable) rules containing 99% of known patterns involved in
website vulnerabilities. For example, <, | or drop are not supposed
to be part of a URI.
Being very simple, those patterns may match legitimate queries, it is the Naxsi's administrator duty to add specific rules that will whitelist legitimate behaviours. The administrator can either add whitelists manually by analyzing nginx's error log, or (recommended) start the project with an intensive auto-learning phase that will automatically generate whitelisting rules regarding a website's behaviour.
In short, Naxsi behaves like a DROP-by-default firewall, the only task is to add required ACCEPT rules for the target website to work properly.
Contrary to most Web Application Firewalls, Naxsi doesn't rely on a signature base like an antivirus, and thus cannot be circumvented by an "unknown" attack pattern. Naxsi is Free software (as in freedom) and free (as in free beer) to use.
Naxsi should be compatible with any nginx version.
It depends on libpcre for its regexp support, and is reported to work great on NetBSD, FreeBSD, OpenBSD, Debian, Ubuntu and CentOS.
The original project is officially abandoned (and has been archived the 8th Nov 2023), but you can fully ask for support here as i'm willing to keep the project working as last remaining developer.
You can find the main documentation here
Be sure when you clone the repository to fetch all the submodules.
$ git clone --recurse-submodules https://github.com/wargio/naxsi.git
$ wget --no-clobber -O nginx.tar.gz "https://nginx.org/download/nginx-1.22.0.tar.gz"
$ mkdir nginx-source
$ tar -C nginx-source -xzf nginx.tar.gz --strip-components=1
$ cd nginx-source
$ ./configure --prefix=/etc/nginx --add-dynamic-module=../naxsi/naxsi_src
$ make
Questions regarding NAXSI can be asked by opening a new issue here
- Bring back nxapi using python3
- Creation of a simple tool to create rules and test them