ModSecurity.io
Open source engine. Production-ready path.

Download ModSecurity.
Get free WAF rules.

Install ModSecurity for Linux, Nginx, Apache, Windows, or IIS, then add maintained rules that work.

Install ModSecurityGet free WAF rules
✓ Apache✓ Nginx✓ IIS✓ Linux & Windows
terminal
# Add the Atomic repository$ sudo wget -q -O -
https://updates.atomicorp.com/installers/atomic
| sudo bash# Install for Apache on RHEL-family Linux$ sudo yum -y install httpd mod_security
● WAF engine ready

Start with what you run

LinuxPackages, not compilersApacheModSecurity 2Nginxlibmodsecurity 3WindowsMSI for IIS
Pick your finish line

From engine to fully managed

Start free. Add faster protection, broader rules, hands-on false-positive fixes, or a complete management layer when you need them.

01

ModSecurity engine

Download free WAF as pre-built Linux and Windows packages. Get ModSecurity without a source build.

Get the engine →
Most practical02

Engine + Atomic rules

Daily CVE and zero-day protections, Layer 7 DDoS defenses, automatic updates, and our Zero False Positive Guarantee.

Why production rules →
03

Complete Atomic WAF

Add centralized management, reporting, tuning, and support when you need a turnkey operational WAF.

Explore Atomic WAF →
Rules built for real traffic

Block attacks.
Keep the site working.

A WAF is useful only when it protects applications without becoming someone’s full-time tuning project. Atomic rules emphasize broad attack coverage, virtual patching, and low operational friction.

See rule options
Request evaluationlive
  • ✓

    Known-safe requestPassed without friction

    ALLOW
  • !

    SQL injection patternAtomic rule 340016

    BLOCK
  • !

    Traversal attemptVirtual patch protection

    BLOCK
  • ✓

    Application API callPassed without friction

    ALLOW
Atomicorp + Varnish

Put the WAF at the edge.

Get Atomic ModSecurity rules, Layer 7 DDoS protection, proof-of-work challenges, CDN delivery, and origin shielding as a hosted service.

Explore the CDN/WAFAsk about white-label service →
Visitor→Varnish CDN
Atomic WAF rules→Your origin
Useful depth, when you need it

Documentation for the engine and the rules

ENGINE REFERENCE

ModSecurity documentation

Configuration, rule language, processing phases, logging, and troubleshooting.

ATOMIC PROTECTION

Atomic rules documentation

Rule IDs, families, CVE research, tuning, updates, and false-positive support.

RESEARCH

WAF research notes

See tested exploit techniques and observed rule interactions.

Ready when you are

Get a WAF running today.

Choose your operating system. We’ll take you straight to the shortest reliable path.

Install on LinuxInstall on Windows