SubDomainFinder icon

Find subdomains of a Domain

The Subdomain Finder from binsec.tools is a fast and reliable tool for discovering subdomains of a target domain. It aggregates results from multiple data sources to give a comprehensive view of a domain's substructure. It's especially useful for reconnaissance, bug bounty hunting, and penetration testing, helping users quickly map out potential attack surfaces. The tool is simple to use and focuses on delivering results without unnecessary complexity. The Subdomain Finder of binsec.tools uses a multi-pronged approach to uncover subdomains:

  • Accesses the CertWatch database — a curated collection of public SSL/TLS certificates — where subdomains often appear in certificate metadata.
  • Performs systematic DNS lookups using a predefined subdomain wordlist to identify commonly used or default subdomains.
  • Sends targeted search queries to Google to discover subdomains that appear in public search results but may be missed by traditional tools.

Go to SubDomainFinder
SubDomainFinder icon

Penetration Testing
Tools

On binsec.tools, you’ll find free online tools for penetration testing – the same ones used by the binsec group in real-world pentests. The publicly available tools are primarily designed to gather information and enrich it with additional data. Check them out!

Penetration Testing

Since 2013 we conduct professional penetration test, based on international industry standards and years of experience in penetration testing, red teaming and hacking.

As a company for professional penetration testing, we do some things differently than other pentest provider: As a penetration test firm, we do not sell vulnerability scans as pentest. We do also focus on business security risks. You are looking for a professionally conducted penetration tests? Get the binsec team for your Pentest. Read more about our pentest service.

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Pentest Knowledge and Tools

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Free pentest tools for your security analysis.

Pentest Tools
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Take a look at our wiki page about pentesting.

Pentest WIKI
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Straight answers to common pentesting questions.

Pentest FAQ

Company

binsec GmbH
Solmsstraße 41
60486 Frankfurt am Main
Germany

Legal notice

Director: Patrick Sauer
Authorised Officer: Florian Zavatzki, Dominik Sauer
Registration: Frankfurt am Main, HRB97277
Turnover Tax Identification No.: DE290966808

© 2025 All rights reserved by binsec GmbH.

© 2025 All rights reserved by binsec GmbH.