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naxsi: NGINX Anti XSS & SQL Injection module

Installation

You can install this module in any RHEL-based distribution, including, but not limited to:

  • RedHat Enterprise Linux 7, 8, 9
  • CentOS 7, 8, 9
  • AlmaLinux 8, 9
  • Rocky Linux 8, 9
  • Amazon Linux 2 and Amazon Linux 2023
yum -y install https://extras.getpagespeed.com/release-latest.rpm
yum -y install nginx-module-naxsi

Enable the module by adding the following at the top of /etc/nginx/nginx.conf:

load_module modules/ngx_http_naxsi_module.so;

This document describes nginx-module-naxsi v1.6 released on Nov 28 2023.

naxsi

What is Naxsi?

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.

Why is it different?

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.

What does it run on?

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.

Why using this repository

The original project is (unofficially) abandoned, but you can fully ask for support here as i'm willing to keep the project working as last remaining developer.

Documentation

docs

Build naxsi

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

Support

You can ask for support regarding NAXSI here or on the original repository https://github.com/nbs-system/naxsi

Future plans

  • Bring back nxapi via py3
  • Creation of a simple tool to create rules and test them

GitHub

You may find additional configuration tips and documentation for this module in the GitHub repository for nginx-module-naxsi.