Find Subdomains

Finding subdomains is fundamental. The more subdomains you find, the bigger attack surface you have. Which means bigger possibility of success.

For now this seems to be a very comprehensive list of tools to find subdomains. https://blog.bugcrowd.com/discovering-subdomains

Some tools find some stuff, other tools other stuff. So your best bet is to use a few of them together. Don't forget to brute-force recursively!

recon-ng

In order to find subdomains we can use the recon-ng framework. It has the same basic structure as metasploit. You can learn more about this tool in the tools-section.

recon-ng

use use recon/domains-hosts/

# This will give you a vast amount of alternatives.

show options

set source cnn.com

All these subdomains will be saved in hosts, which you can access though: show hosts

If some of these subdomains are not given IPs automatically you can just run

use recon/hosts-hosts/resolve
run

And it will resolve all the hosts in the hosts-file.

Google Dorks

Using google we can also find subdomains.

This will only give us the subdomains of a site.

site:msn.com -site:www.msn.com

site:*.nextcloud.com

To exclude a specific subdomain you can do this:

site:*.nextcloud.com -site:help.nextcloud.com

subbrute.py

The basic command is like this

./subbrute.py -p cnn.com

https://github.com/TheRook/subbrute

Knock

I haven't tested this yet. https://github.com/guelfoweb/knock

Being smart

You also have to look at what kind of system the target has. Some web-apps give their clients their own subdomains. Like github.

Check out the homepage Often companies brag about their clients. You can use this to guess the subdomains of some clients.

Reverse DNS-lookup

If you manage to figure out the IP range that the target owns (see section about nmap below). You can see which machines are online. And then you can run a script to find out the domain-addresses of those machines. That way you might find something new.

The text-file onlyIps.txt is a textfile with one IP-address on each line.

#!/bin/bash

while read p; do
  echo $p;
  host  $p
done <onlyIps.txt

Here are some more tools that can do reverse lookup http://www.cyberciti.biz/faq/how-to-test-or-check-reverse-dns/

Online tools

DNSStuff

This tool doesn't enumerate subdomains per se. But it hands of a lot of information about domains. http://www.dnsstuff.com/

Bypassing CloudFlare

https://www.ericzhang.me/resolve-cloudflare-ip-leakage/

This tool can be used to find old IPs. It could mean that the http://toolbar.netcraft.com/site_report?url=lyst.com

Brute force dictionaries

If you try to brute force the domains it is a good idea to have a good dictionary. That can be found here:

Bitquark https://github.com/bitquark/dnspop

SecList https://github.com/danielmiessler/SecLists/tree/master/Discovery/DNS

References

https://en.wikipedia.org/wiki/CNAME_record

Finding subdomains