Subfinder

Subfinder is a subdomain discovery tool that discovers valid subdomains for websites by using passive online sources. It has a simple modular architecture and is optimized for speed. subfinder is built for doing one thing only - passive subdomain enumeration, and it does that very well.

Fast passive subdomain enumeration tool.

Subfinder is a subdomain discovery tool that discovers valid subdomains for websites by using passive online sources. It has a simple modular architecture and is optimized for speed. subfinder is built for doing one thing only - passive subdomain enumeration, and it does that very well.

We have designed subfinder to comply with all passive sources licenses, and usage restrictions, as well as maintained a consistently passive model to make it useful to both penetration testers and bug bounty hunters alike.

Features

• Fast and powerful resolution and wildcard elimination module
• Curated passive sources to maximize results
• Multiple Output formats supported (Json, File, Stdout)
• Optimized for speed, very fast and lightweight on resources
• STDIN/OUT support for integrating in workflows

Usage

subfinder -h

This will display help for the tool. Here are all the switches it supports.

Installation

Subfinder requires go1.14+ to install successfully. Run the following command to get the repo -

▶ GO111MODULE=on go get -v github.com/projectdiscovery/subfinder/v2/cmd/subfinder

Post Installation Instructions

Subfinder will work after using the installation instructions however to configure Subfinder to work with certain services, you will need to have setup API keys. The following services do not work without an API key:

• Binaryedge
• Certspotter
• Censys
• Chaos
• DnsDB
• Github
• Intelx
• Passivetotal
• Recon.dev
• Robtex
• SecurityTrails
• Shodan
• Spyse
• Threatbook
• Virustotal
• Zoomeye

Theses values are stored in the $HOME/.config/subfinder/config.yaml file which will be created when you run the tool for the first time. The configuration file uses the YAML format. Multiple API keys can be specified for each of these services from which one of them will be used for enumeration.

For sources that require multiple keys, namely Censys, Passivetotal, they can be added by separating them via a colon (:).

An example config file -

resolvers:
  - 1.1.1.1
  - 1.0.0.1
sources:
  - binaryedge
  - bufferover
  - censys
  - passivetotal
  - sitedossier
binaryedge:
  - 0bf8919b-aab9-42e4-9574-d3b639324597
  - ac244e2f-b635-4581-878a-33f4e79a2c13
censys:
  - ac244e2f-b635-4581-878a-33f4e79a2c13:dd510d6e-1b6e-4655-83f6-f347b363def9
certspotter: []
passivetotal:
  - [email protected]:sample_password
securitytrails: []
shodan:
  - AAAAClP1bJJSRMEYJazgwhJKrggRwKA
github:
  - d23a554bbc1aabb208c9acfbd2dd41ce7fc9db39
  - asdsd54bbc1aabb208c9acfbd2dd41ce7fc9db39

Running Subfinder

To run the tool on a target, just use the following command.

▶ subfinder -d example.com

The verbose flag v can be used to display verbose information.

[bufferover] lutin.dima.example.com
[bufferover] izosimdima.example.com
[bufferover] glazkovdima.example.com
[bufferover] dengshima.example.com
[bufferover] wwwkima.example.com
[bufferover] proxima.example.com
[bufferover] mma.example.com
[bufferover] damidoma.example.com
[bufferover] nomerdoma.example.com
[bufferover] soti.croma.example.com

The -o command can be used to specify an output file.

▶ subfinder -d example.com -o output.txt

To run the tool on a list of domains, -dL option can be used. This requires a directory to write the output files. Subdomains for each domain from the list are written in a text file in the directory specified by the -oD flag with their name being the domain name.

▶ cat domains.txt
hackerone.com
google.com
▶ subfinder -dL domains.txt -oD ~/path/to/output
▶ ls ~/path/to/output
hackerone.com.txt
google.com.txt

You can also get output in json format using -oJ switch. This switch saves the output in the JSON lines format.

If you use the JSON format, or the Host:IP format, then it becomes mandatory for you to use the -nW format as resolving is essential for these output format. By default, resolving the found subdomains is disabled.

▶ subfinder -d hackerone.com -o output.json -oJ -nW
▶ cat output.json
{"host":"www.hackerone.com","ip":"104.16.99.52"}
{"host":"mta-sts.hackerone.com","ip":"185.199.108.153"}
{"host":"hackerone.com","ip":"104.16.100.52"}
{"host":"mta-sts.managed.hackerone.com","ip":"185.199.110.153"}

The subdomains discovered can be piped to other tools too. For example, you can pipe the subdomains discovered by subfinder to httpx httpx which will then find running http servers on the host.

▶ echo hackerone.com | subfinder -silent | httpx -silent
http://hackerone.com
http://www.hackerone.com
http://docs.hackerone.com
http://api.hackerone.com
https://docs.hackerone.com
http://mta-sts.managed.hackerone.com

▶ docker pull projectdiscovery/subfinder

docker build -t projectdiscovery/subfinder .

▶ mkdir -p $HOME/.config/subfinder
▶ cp config.yaml $HOME/.config/subfinder/config.yaml
▶ nano $HOME/.config/subfinder/config.yaml

▶ docker run -v $HOME/.config/subfinder:/root/.config/subfinder -it projectdiscovery/subfinder -d example.com

docker run -v $HOME/.config/subfinder:/root/.config/subfinder -it projectdiscovery/subfinder -d example.com > example.com.txt

package main
import (
	"bytes"
	"context"
	"fmt"
	"io"
	"io/ioutil"
	"log"
	"github.com/projectdiscovery/subfinder/v2/pkg/passive"
	"github.com/projectdiscovery/subfinder/v2/pkg/resolve"
	"github.com/projectdiscovery/subfinder/v2/pkg/runner"
)
func main() {
	config := runner.ConfigFile{
		// Use the default list of resolvers by marshaling it to the config
		Resolvers: resolve.DefaultResolvers,
		// Use the default list of passive sources
		Sources: passive.DefaultSources,
		// Use the default list of all passive sources
		AllSources: passive.DefaultAllSources,
		// Use the default list of recursive sources
		Recursive: passive.DefaultRecursiveSources,
	}
	runnerInstance, err := runner.NewRunner(&runner.Options{
		Threads:            10, // Thread controls the number of threads to use for active enumerations
		Timeout:            30, // Timeout is the seconds to wait for sources to respond
		MaxEnumerationTime: 10, // MaxEnumerationTime is the maximum amount of time in mins to wait for enumeration
		YAMLConfig:         config,
	})
	buf := bytes.Buffer{}
	err = runnerInstance.EnumerateSingleDomain(context.Background(), "projectdiscovery.io", []io.Writer{&buf})
	if err != nil {
		log.Fatal(err)
	}
	data, err := ioutil.ReadAll(&buf)
	if err != nil {
		log.Fatal(err)
	}
	fmt.Printf("%s", data)
}

DEVELOPER DO NOT SUPPORT ANY OF THE ILLEGAL ACTIVITIES.

Contact Me on telegram or twitter: https://twitter.com/TrewisScotch / https://t.me/HiroSCOTCH#