Understanding Subdomain Squatting

All you need to know about subdomain squatting

4 min readMar 22, 2024

As a website owner or administrator, managing your online presence involves more than just securing a catchy domain name. It requires vigilance in maintaining your Domain Naming System (DNS) to prevent potential security risks, such as subdomain squatting. Let’s break it down:

firstly let’s understand what things a DNS holds. I am using securitytrails to find the dns data of medium.com.

“A” Record: Maps domain names to IPv4 addresses, enabling connections to websites or services using IPv4

“AAAA” Record: It maps a domain name to an IPv6 address, enabling devices to connect to websites or services using IPv6, which offers a larger address space compared to IPv4.

“MX” Record: It specifies mail servers responsible for receiving email on behalf of a domain, directing email traffic to the appropriate servers for delivery.

“NS” Record: It identifies authoritative name servers for a domain, indicating where DNS information for that domain is stored and providing a mechanism for resolving domain name queries.

“SOA” Record: It contains essential information about a DNS zone, including the primary authoritative name server for the zone, contact information for the responsible party, and details about the zone’s refresh and expiry intervals.

“TXT” Record: It allows domain owners to add arbitrary text information to a domain’s DNS records, often used for verification purposes, setting domain-wide policies, or providing additional information about a domain.

“CNAME” Record: It creates an alias for one domain name to another, enabling multiple domain names to point to the same location, useful for creating shortcuts or managing website migrations without changing IP addresses.

What is Subdomain Squatting?

  • Subdomain squatting occurs when attackers exploit unused or “dangling” subdomains within your domain’s DNS entries.
  • Attackers identify abandoned subdomains and claim ownership, effectively occupying the space you’ve left vacant.

Why Does it Matter?

  • Subdomain squatting opens the door for malicious activities, such as phishing attacks or the distribution of malware.
  • Attackers can leverage stolen subdomains to deceive visitors and potentially compromise sensitive data.

How Does it Happen?

  • When resources like web pages or services are de-provisioned but their DNS entries remain active, creating a vulnerability.
  • Failure to promptly remove or update DNS entries for unused subdomains leaves them susceptible to exploitation.

Imagine a company plans to launch a blog on Medium but later abandons the idea, leaving the subdomain example-blog.medium.com unclaimed. Others could register it and use it for malicious purposes like phishing or malware distribution. This practice, known as DNS squatting, underscores the importance of vigilant domain management.

Best Practices

  • Regularly audit and clean up your DNS records to remove unused subdomains.
  • Implement monitoring systems to detect unauthorized changes or suspicious activity within your DNS.
  • Educate your team on the importance of promptly communicating changes to IT or DNS administrators to ensure timely updates.

Taking Action: Mitigating Subdomain Squatting Risks

  • Utilize security tools and services that offer domain monitoring and alerting capabilities to identify potential squatting attempts.
  • Consider implementing DNS security solutions, such as DNSSEC (Domain Name System Security Extensions), to enhance the integrity and authenticity of your DNS records.
  • Stay informed about emerging threats and evolving best practices in DNS management and cybersecurity to proactively safeguard your online assets.

In the ever-evolving landscape of threats, maintaining a proactive approach to DNS management is essential to fortify your organization’s digital defenses and preserve trust in your online brand. Don’t let abandoned subdomains become a backdoor for malicious actors.

That’s all for this see you in next post.

keep the bytes…




"Tech enthusiast exploring cybersecurity and networking. Sharing insights through the power of words. Join me in the world of tech and discovery. 📚✍️