Domain Name Service (DNS) is an often-misunderstood part of network infrastructure. Too often misconfiguration of DNS can lead to massive issues in your network. Subdomain takeovers are too common especially in large organizations that create and delete many resources. Malicious actors often use these sites to redirect traffic and activity to various other sites. Microsoft notes that exposing yourself to subdomain takeover starts when you set up and provision an Azure resource. Attackers use various tools and scripts to search for and find these subdomains.”]
Source: https://www.csoonline.com/article/3601007/how-to-avoid-subdomain-takeover-in-azure-environments.html