Alvin bijo
1 min readJan 1, 2024

Exploring the Depths: DNS Wildcard and Subdomai

In this in-depth exploration, we unravel the intricacies of DNS wildcard configurations and their associated risks. Discover how attackers exploit these settings, especially when CNAME records come into play, enabling subdomain takeovers.

## Understanding DNS Wildcard

When a domain utilizes a DNS wildcard, any requested subdomain not explicitly defined resolves to the same information. For instance, if `*.testing.com` is wildcarded to `1.1.1.1`, then `not-existent.testing.com` points to `1.1.1.1`.

## Exploiting CNAME Records

Take it a step further: imagine the sysadmin directs the wildcard to a third-party service via CNAME, like a GitHub subdomain (`sohomdatta1.github.io`). An attacker can create a matching third-party page, claiming that `something.testing.com` points there. Exploiting the CNAME wildcard, the attacker generates arbitrary subdomains, pointing them to their own pages.

### Real-world Examples

Let's delve into real-world cases where this vulnerability has been exploited, showcasing the potential impact and consequences of subdomain takeovers.

## Mitigating Security Risks

Stay ahead of the game with effective strategies to mitigate the security risks associated with DNS wildcards and subdomain takeovers. Protect your domains from unauthorized subdomain manipulations.

Knowledge is power—empower yourself against potential threats in the dynamic landscape of DNS vulnerabilities.

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