DNS Records: Their Crucial Role in Subdomain Takeover


The Domain Name System (DNS) is the phonebook of the internet, translating human-friendly domain names into IP addresses that computers use to communicate. However, misconfigurations in DNS records can lead to serious cybersecurity threats, such as subdomain takeover. This article delves into the crucial role of DNS records in subdomain takeover and how to secure them.

Understanding DNS Records

DNS records are instructions that live in authoritative DNS servers and guide internet traffic to the correct locations. They form an essential part of how the internet works, ensuring that internet users reach the correct websites when they type in a URL. There are several types of DNS records, each serving a different purpose:

  1. A Records: The ‘A’ stands for ‘address’ and this record is used to direct a domain or subdomain to an IP address, which represents a server where the website is hosted.
  2. AAAA Records: Similar to A records, but AAAA records map a domain or subdomain to an IPv6 address, a newer version of IP addresses.
  3. CNAME Records: The ‘CNAME’ stands for ‘canonical name’ and this record is used to alias one domain to another. For example, you might have a mobile version of your website with the subdomain ‘m.example.com’ that points to ‘mobile.example.com’.
  4. MX Records: The ‘MX’ stands for ‘mail exchange’ and this record is used to direct emails to the correct mail servers based on the recipient’s domain.
  5. TXT Records: TXT records are used to hold text information for a server to read. This can include things like verifying domain ownership and ensuring email security.
  6. NS Records: NS stands for ‘name server’ and this record indicates which DNS server is authoritative for that domain (i.e., where the DNS records are stored).
  7. SOA Records: The ‘SOA’ stands for ‘Start of Authority’ and this record contains administrative information about the domain, such as the primary name server, contact details, and various timers and counters associated with the domain.

However, when these records are not properly managed or configured, they can leave a domain or subdomain vulnerable to cyber threats like subdomain takeover.

The Role of DNS Records in Subdomain Takeover

Subdomain takeover typically occurs when a subdomain points to a service (like a web host or cloud service), but the service is no longer used or has been deleted. This is often due to a CNAME record pointing to a non-existent destination. Cybercriminals can exploit this by claiming the abandoned service and taking control of the subdomain.

Securing DNS Records

Securing DNS records is a crucial step in preventing subdomain takeover. Here are some strategies:

  1. Regular Auditing: Regularly check DNS records for any that are outdated or point to unused services.
  2. Use DNSSEC: The Domain Name System Security Extensions (DNSSEC) can protect against DNS spoofing and other forms of cyberattacks.
  3. Access Control: Limit who has access to your DNS records to prevent unauthorized changes.
  4. Monitor for Changes: Use automated tools to monitor DNS records and alert you to any changes.


DNS records play a crucial role in the functioning of the internet, but they can also be a point of vulnerability if not properly managed. By understanding the role of DNS records in subdomain takeover and implementing strategies to secure them, you can protect your online presence from potential threats.

Product Spotlight

To help you in your cybersecurity efforts, consider using bspeka’s Subdomain Takeover Monitor. This tool continuously monitors your subdomains for potential vulnerabilities, helping you to secure your DNS records and prevent subdomain takeover.