What Is Subdomain Takeover and How Does It Happen?

What Is Subdomain Takeover and How Does It Happen? – Subdomain takeover is an important susceptibility in web security that appears when an attacker gets control over a subdomain of a website that has been misplaced or not properly managed. In such conditions, the subdomain, even so inactive or unregulated, can still be selected by attackers. By the takeover, the attacker can host malevolent content, run phishing campaigns, or implement other harmful activities. Knowing the technical mechanisms behind subdomain takeover, its dangers, and protective measures is important to securing web assets from such a severe threat. In this blog we will know What is Subdomain Takeover and How Does it Happen.

What are Subdomains?

To get the concept of a subdomain takeover, it is important to first understand what a subdomain is. In the DNS domain name system, a domain name is an address that identity to a website. For instance, example.com is the key domain name. A subdomain is a part of this bigger domain and occurs before the main domain. Companies sometimes use subdomains to evolve different sections of their website, such as making a subdomain for customer support, a blog, or an e-commerce store.

How Subdomain Takeovers Happen

Subdomain takeovers mainly appear due to mispositioning in DNS records. These takeovers take benefit of a situation where a subdomain is connected to a service or platform that is no longer in use, but the DNS records have not been updated to return that. Here is a specific scenario of how a subdomain takeover happens:

Remaining Subdomains and CNAME Records

Various websites and firms depend on third-party platforms for hosting services or attributes. For instance, a company may host a blog on a service like Medium or WordPress, using a subdomain such as blog.example.com. The company then makes a CNAME (Canonical Name) DNS record referring blog.example.com to the WordPress platform. Thus, if the company stops the service but fails to detach or update the DNS record, the subdomain still subsists and points to a service that is no longer maintained.

Desertion of Services

When a firm stops using a third-party service like GitHub Pages, WordPress, or an Azure-hosted service, they might disuse to update their DNS records. These third-party services sometimes release remaining resources for others to claim. However, the DNS records still connect the subdomain (blog.example.com) with the stopped service.

Attackers Identify Attackable Subdomains

Attackers scan websites and networks for subdomains that are misplaced and pointing to unidentified services. Once they find a subdomain pointing to an unnamed service or platform, they can take over the subdomain by entering it via the third-party service, successfully maintaining the subdomain without having entrance to the primary domain.

Claiming the Service

Once an attacker recognizes a subdomain pointing to an unnamed or inhibited service, they can enter the service on the platform that the subdomain refers to. For instance, if blog.example.com was pointing to an unnamed WordPress site, the attacker can sign up for a WordPress account and get the blog.example.com subdomain. Since the DNS record has not been updated, the subdomain now points to the attacker’s latest registered account.

Utilize the Takeover

After effectively claiming the subdomain, the attacker can upload spiteful content, host phishing websites, inject spam, or make fake pages that trick users into disclosing sensitive information. Since the subdomain still connects to the legal website in the DNS organization, users are more likely to believe it.

Platforms Attakable to Subdomain Takeover

Specific platforms and services are mainly targeted for subdomain takeovers, particularly when firms fail to remove DNS records after stopping the service. Some basic platforms include:

• GitHub Pages – Various firms use GitHub Pages for hosting documentation or websites. If the storage linked to a subdomain is deleted or made private, the subdomain can be taken over by making a new storage with the same name.
• AWS (Amazon Web Services) – AWS enables users to host websites or services via S3 buckets. If an S3 bucket linked to a subdomain is removed, the subdomain may become unsafe to take over if an attacker makes a new bucket with the same name.
• Heroku – Heroku is a cloud platform used to position applications. If an application on Heroku is removed or unused without updating the DNS, attackers can get the subdomain by entering an application with the same name.
• Azure – Microsoft Azure is another famous platform that may be unsafe for subdomain takeovers, specifically when firms fail to manage DNS records completely after removing services hosted on Microsoft Azure.

Conclusion 

Subdomain takeover is a severe threat that can have important security and reputational suggestions for firms. It appears due to the mismanagement of DNS records, enabling attackers to get control over deserted or unregulated subdomains. By following best uses such as constant audits, prompt DNS record removal, and complete security monitoring, firms can reduce the risk of subdomain takeovers and save their web assets from misuse. Understanding What Is Subdomain Takeover and How Does It Happen and being focused on managing DNS organization are key elements in managing a safe and reliable online presence.

FAQs

• Can subdomains be hacked by anyone?

A subdomain takeover appears when an attacker gets maintenance over a subdomain of a target domain.

• What are the restrictions of a Subdomain?

Every subdomain can be up to 255 characters long, but for multi-layered subdomains, every level can only be 63 characters long.

• What is the motive of a subdomain?

A subdomain is a lead added to a domain name to part a section of your website.

• Does a subdomain influence SEO?

Choosing between a subdomain and a subdirectory can importantly affect your site’s SEO activity.