SantoDE / coraza-waf

Coraza WAF is a golang modsecurity compatible web application firewall library

Coraza Web Application Firewall

Welcome to Coraza Web Application Firewall, this project is a Golang port of ModSecurity with the goal to become the first enterprise-grade Open Source Web Application Firewall, flexible and powerful enough to serve as the baseline for many projects.

Prerequisites

• Linux distribution (Debian and Centos are recommended, Windows is not supported)
• Golang compiler v1.16+

Optional Prerequisites

In this Coraza version, you can set CGO_ENABLED to 1 or 0, if you set it to 1, you will be required to link libinjection and libpcre to enable PCRE expressions, @detectSQLi and @detectXSS, if you set it to 0 you won't need any dynamic library but your implementation won't support @detectSQLi, @detectXSS nor PCRE expressions, which means OWASP CRS won't work.

Future versions of Coraza will fully remove CGO.

	CGO Enabled	CGO Disabled
@detectSQLi	Yes	No
@detectXSS	Yes	No
PCRE regex	Yes	No
RE2 regex	Yes	Yes
OWASP CRS	Yes	No

If you want to install Coraza with CGO support, you will need:

• libpcre-dev (apt install libpcre++-dev for Ubuntu)
• CGO_ENABLED environmental variable must be set to 1
• libinjection must be installed and linked

Running the tests

Run the go tests:

go test ./...
go test -race ./...

Run the test suite against OWASP CRS

You can run the testsuite using our OWASP CRS test docker image, it will run a Coraza instance using Caddy and go-ftw

git clone https://github.com/jptosso/coraza-ruleset
cd coraza-ruleset
docker build . -t crs
docker run crs -name crs

You may also use our testesuite

Your first Coraza WAF project

Make sure CGO_ENABLED=1 env is set before compiling and all dependencies are met.

package main
import(
	"fmt"
	engine"github.com/jptosso/coraza-waf"
	"github.com/jptosso/coraza-waf/seclang"
)

func main() {
	// First we initialize our waf and our seclang parser
	waf := engine.NewWaf()
	parser := seclang.NewParser(waf)

	// Now we parse our rules
	parser.FromString(`SecRule REMOTE_ADDR "@rx .*" "id:1,phase:1,drop"`)

	// Then we create a transaction and assign some variables
	tx := waf.NewTransaction()
	tx.ProcessConnection("127.0.0.1", 8080, "127.0.0.1", 12345)

	tx.ProcessRequestHeaders()

	// Finally we check the transaction status
	if tx.Interrupted() {
		fmt.Println("Transaction was interrupted")
	}
}

Integrate with any framework

Using the standard net/http library:

package main
import(
	engine"github.com/jptosso/coraza-waf"
	"github.com/jptosso/coraza-waf/seclang"
	"net/http"
)

func SomeErrorPage(w http.ResponseWriter) {
	w.WriteHeader(403)
	w.Write([]byte("WAF ERROR")
}

func someHandler(waf *engine.Waf) http.Handler {
  return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
    tx := waf.NewTransaction()
	tx.ProcessRequest(r)
	if tx.Interruption != nil {
		SomeErrorPage(w)
	}
  })
}

Responses are harder to handle, because we must intercept the response writers and integrate them with the Coraza BodyReader.

Handling HTTP responses with Coraza

Responses are usually long buffers, so duplicating the response or buffering it in memory is hard. In order to avoid issues while handling long buffers Coraza provides the engine.BodyReader struct, it will handle long buffers storing them to temporary files if needed.

func someHandler(waf *engine.Waf) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		tx := waf.NewTransaction()
		tx.ProcessRequest(r)
		if tx.Interruption != nil {
			SomeErrorPage(w)
		}
		// We will use the Coraza response reader:
		tx.ProcessResponseHeaders()
		tx.ResponseBuffer.Write([]byte("Some of the response body"))
		tx.ProcessResponseBody()
		// We will dump the buffered response into the response writer:
		io.Copy(w, tx.ResponseBuffer)
	})
}

Compatibility status

We are fully compatible with OWASP CRS, except by DDOS and anti-bot protection.

Why Coraza WAF?

Philosophy

• Simplicity: Anyone should be able to understand and modify Coraza WAF's source code
• Extensibility: It should be easy to extend Coraza WAF with new functionalities
• Innovation: Coraza WAF isn't just a ModSecurity port, it must include awesome new functions (in the meantime it's just a port 😅)
• Community: Coraza WAF is a community project and everyone's idea will be heard

Roadmap (long term)

• WASM scripts support, Lua was removed
• Performance improvements
• More tests and documentation
• Integrated DDOS protection and directives with iptables(And others) integration
• Integrated protocol validations (rfc2616)
• Integrated CSRF protection
• Integrated bot detection with captcha
• More loggers and persistence engines
• More integrations (traefik and buffalo)
• Open Policy Agent package (OPA)
• Enhanced rule profiling
• Native antivirus integration (maybe)
• Automatic coreruleset integration (download and setup) (maybe)
• Enhanced data masking features
• Enhanced data signing features (cookies, forms, etc)
• OpenAPI enforcement
• JWT enforcement
• JSON and YAML query

Coraza WAF implementations

• Caddy Plugin (Reverse Proxy and Web Server) (Stable)
• Traefik Plugin (Reverse Proxy and Web Server) (not working yet)
• Gin Middleware (Web Framework) (Preview)
• Buffalo Plugin (Web Framework) (soon)

## Coraza Plugins

• coraza-bluemonday: Detect bluemonday policy failures with the @htmlPolicy operator. This is a testing plugin.

Some useful tools

• Go FTW: rule testing engine
• Coraza Playground: rule testing sandbox with web interface

Troubleshooting

How to contribute

Contributions are welcome, there are so many TODOs, also functionalities, fixes, bug reports and any help you can provide. Just send your PR.

cd /path/to/coraza
egrep -Rin "TODO|FIXME" -R --exclude-dir=vendor *

Useful links

Special thanks

• Modsecurity team for creating SecLang
• OWASP Coreruleset team for the CRS and their feedback

About

The name Coraza is trademarked, Coraza is a registered trademark of Juan Pablo Tosso.

• Author on Twitter @jptosso