CRLFuzz
A fast tool to scan CRLF vulnerability written in Go
Resources
Installation
from Binary
The installation is easy. You can download a prebuilt binary from releases page, unpack and run! or with
▶ curl -sSfL https://git.io/crlfuzz | sh -s -- -b /usr/local/bin
from Source
If you have go1.13+ compiler installed and configured:
▶ GO111MODULE=on go get -v github.com/dwisiswant0/crlfuzz/cmd/crlfuzz
In order to update the tool, you can use -u flag with go get command.
from GitHub
▶ git clone https://github.com/dwisiswant0/crlfuzz
▶ cd crlfuzz/cmd/crlfuzz
▶ go build .
▶ mv crlfuzz /usr/local/bin
Usage
Basic Usage
Simply, CRLFuzz can be run with:
▶ crlfuzz -u "http://target"
Flags
▶ crlfuzz -h
This will display help for the tool. Here are all the switches it supports.
| Flag | Description |
|---|---|
| -u, --url | Define single URL to fuzz |
| -l, --list | Fuzz URLs within file |
| -X, --method | Specify request method to use (default: GET) |
| -o, --output | File to save results |
| -d, --data | Define request data |
| -H, --header | Pass custom header to target |
| -x, --proxy | Use specified proxy to fuzz |
| -c, --concurrent | Set the concurrency level (default: 25) |
| -s, --silent | Silent mode |
| -v, --verbose | Verbose mode |
| -V, --version | Show current CRLFuzz version |
| -h, --help | Display its help |
Target
You can define a target in 3 ways:
Single URL
▶ crlfuzz -u "http://target"
URLs from list
▶ crlfuzz -l /path/to/urls.txt
from Stdin
In case you want to chained with other tools.
▶ subfinder -d target -silent | httpx -silent | crlfuzz
Method
By default, CRLFuzz makes requests with GET method. If you want to change it, you can use the -X flag.
▶ crlfuzz -u "http://target" -X "GET"
Output
You can also save fuzzing results to a file with -o flag.
▶ crlfuzz -l /path/to/urls.txt -o /path/to/results.txt
Data
If you want to send a data request using POST, DELETE. PATCH or other methods, you just need to use -d flag.
▶ crlfuzz -u "http://target" -X "POST" -d "data=body"
Adding Headers
May you want to use custom headers to add cookies or other header parts.
▶ crlfuzz -u "http://target" -H "Cookie: ..." -H "User-Agent: ..."
Using Proxy
Using a proxy, proxy string can be specified with a protocol:// prefix to specify alternative proxy protocols.
▶ crlfuzz -u "http://target" -x http://127.0.0.1:8080
Concurrency
Concurrency is the number of fuzzing at the same time. Default value CRLFuzz provide is 25, you can change it by using -c flag.
▶ crlfuzz -l /path/to/urls.txt -c 50
Silent
If you activate this silent mode with the -s flag, you will only see vulnerable targets.
▶ crlfuzz -l /path/to/urls.txt -s | tee vuln-urls.txt
Verbose
Unlike silent mode, it will display error details if there is an error with the -v flag.
▶ crlfuzz -l /path/to/urls.txt -v
Version
To display the current version of CRLFuzz with the -V flag.
▶ crlfuzz -V
Library
You can use CRLFuzz as a library.
package main
import (
"fmt"
"github.com/dwisiswant0/crlfuzz/pkg/crlfuzz"
)
func main() {
target := "http://target"
method := "GET"
// Generates a potentially CRLF vulnerable URLs
for _, url := range crlfuzz.GenerateURL(target) {
// Scan against target
vuln, err := crlfuzz.Scan(url, method, "", []string{}, "")
if err != nil {
panic(err)
}
if vuln {
fmt.Printf("VULN! %s\n", url)
}
}
}
Help & Bugs
If you are still confused or found a bug, please open the issue. All bug reports are appreciated, some features have not been tested yet due to lack of free time.
License
CRLFuzz released under MIT. See LICENSE for more details.
Version
Current version is 1.4.0 and still development.
![[BUG] net/url: invalid control character in URL](https://avatars.githubusercontent.com/u/76052370?v=4)
