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AshleyMartin
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Jan 30, 2023

New Blog Post | Identify Digital Assets Vulnerable to Subdomain Takeover

 

 

Read the full blog post: Identify Digital Assets Vulnerable to Subdomain Takeover - Microsoft Community Hub

 

Subdomain takeover vulnerabilities are, in most cases, the result of an organization using an external service and letting it expire. However, that expired subdomain is still a part of the organization's external attack surface, with domain DNS entries pointing to it. An attacker could then claim this subdomain and take control of it with little to no effort, a considerable blow to an organization's security posture.

 

How does this happen? For example, a company might enlist a service desk provider, "FreshDesk.' It would point a subdomain like "support.mycompany.com" to FreshDesk and then claim this domain with the Freshdesk service to activate it. However, a problem arises when the organization abandons the service because they migrate to other services or for some other reason. Meanwhile, after the service agreement expires, the subdomain remains pointing to the FreshDesk platform.

 

While this might not seem bad initially, the risk of allowing attackers to execute scripts under the subdomain enables them to obtain data from the main website. The risk becomes even more significant when this scenario involves a service that handles PPI, PHI, or trade secrets. Microsoft Defender External Attack Surface Management continuously maps the external-facing resources across your organization's attack surface to identify, classify, and prioritize risks, including subdomain expiration and takeover.

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