How to Find Subdomains Instantly and Why Do Not Neglect That
Some honest facts about popular methods of subdomain enumeration and tips on how not to spend the entire life on it.
Who would have thought subdomains could become a threat to one’s cybersecurity? Evidently, not these guys from Epic Games whose subdomains were hijacked by an old good hacker team. The compromised application claim has been rejected because, honestly, who cares about users’ stolen passwords and their hacked accounts?
The measure of the company’s risk of hacked subdomains can reach a lower or higher degree. And sometimes, only luck would help save reputation. Or timely subdomain lookup and check.
Why Should Find Subdomains?
What are subdomains?
Subdomains are parts of larger domains. Subdomains are used to structure different sections or versions of the website and might contain some interesting insights for those seeking. For example, experimental products appear on the subdomains long before releasing on the main website; different website versions could provide interesting data about new partners, connections, etc.
That’s why they are valuable digital assets and may tell a lot about a specific target. For the record, domains and subdomains may belong to different Top-level domain zones.
Finding subdomains is an essential step in cyber reconnaissance, so neglecting them can cause backfire on any enterprise:
- Stolen users’ personal and sensitive data
- Subdomains takeovers used for malicious content
- Corporate espionage
- Valuable data leakage, etc.
Ethical hackers, developers, and cybersecurity engineers find subdomains for numerous intents and purposes:
- Expand an attack surface
- Perform a reconnaissance for finding more potential attack vectors and extra targets
- Find existing system vulnerabilities
- Evaluate the cybersecurity risks
- Assess the digital assets and find unknown ones
Subdomain Enumeration and Its Popular Methods
Subdomain enumeration is an operation to find all subdomains of a domain.
Here are the most popular methods to enumerate subdomains:
- Brute forcing. A method to generate a subdomain list when there’s no other business and you don’t value your time much. Take a dictionary, test words… and who knows, maybe you’ll get lucky one day.
- Certificate transparency. Certificate Authority (CA) publishes all issued SSL/TLS certificates to domains and subdomains. Use any search engine that collects information about certificates to find subdomains associated with them.
- DNS zone transfer. The technique can be used to find subdomains on a DNS server, which zone is unprotected.
Terminal-based subdomain scanner tools
Terminal-based subdomain scanners are great tools to find large amounts of data. It does work when there is a single target to explore. But when it comes to a list of targets, most terminal-based tools meet the rate limit. That explains the small number of allowed requests and why the price for extra ones is too high.
Best terminal-based subdomain finders
- Amaas. Amaas is on top of command tools for a good reason – it’s helpful to find large amounts of subdomain data. It includes different techniques, such as brute-forcing and machine learning.
- Sublist3r. Sublist3r is a fast and useful tool to collect subdomain data. It scans within minutes and returns with a massive list of found information.
- Knock. ‘Knock-knock – Who’s there?’ – that could be a request example of Knock Python-based program. But it’s far more interesting – Knock works with a full DNS zone to find subdomains for you.
The main idea that comes across all terminal-based subdomain scanner tools is their ability to find a vast amount of data. It’s rarely a significant advantage because you need to filter out dead subdomains to find relevant manually.
Editors’ advice: find a tool that will save you time, provide qualitative and filtered data, and give you extra insights about your target.
Web-tools to search subdomains
Web tools are more flexible in utilizing, and it’s always a good idea to find relevant information fast and get linked data that can lead you to the additional targets.
Popular web-tools in this case are:
- Google hacking techniques. This method allows for finding indexed subdomains related to a domain by a simple Google search: site:example.com.
- DNSdumpster. DNSdumpster doesn’t use a brute-forcing method but open-source intelligence to find subdomains related to a domain. It succeeds at the task fast, but don’t expect to get more than DNS records and subdomains.
- Censys. Wide-known web-tool to find technical information, including the subdomain list. It associates domains with a certificate and gives immediate results.
Find Subdomains in 3…2…1 🚀
If you don’t want to spend the entire life while searching for subdomains, here’s a tip for you: use the subdomain finder of Spyse with its huge database of relevant data. Spyse has developed the biggest database of its kind to provide something more significant than a simple subdomain finder. By searching subdomains through Spyse, infosec experts receive a solution for a large part of the security assessment process.
Main capabilities with Spyse Subdomain Finder:
- Instant results, immediate response
- Enriched data with Site Title, Status Code, etc.
- Active, live subdomains
- Advanced Search tool to specify a query and narrow down results.
- Ability to integrate API into your infrastructure
Subdomains are valuable digital assets, so there’s no good reason to take them out of control. Finding subdomains with their security assessment is vital for enterprises that value their reputation and work on risk management. That’s why it’s crucial to find the most useful subdomain finder, whether it’s a terminal-based or a web tool.
Check your assets, evaluate your infrastructure’s vulnerabilities, and stay secure with Spyse.