Subdomain Hijacking
In this case the other party would be an attacker by doing so they can deface or redirect users.
Subdomain hijacking. Technically you could call it domain hijacking but that term has a broader meaning with the default connotation being a domain name s registration being overtaken by an attacker. Exposing the risks of hijacking microsoft subdomains is not new it s a problem that dates back years. A subdomain takeover is considered a high severity threat and boils down to the registration of a domain by somebody else with bad intentions by doing this the hacker can take full control of the subdomains.
First the sheer scale of the exposure. With the working subdomain the attacker was able to harvest the authentication token from an existing active ea session before exploiting it directly and in real time. Sub domain hijack issue.
But two things are new. Hijack takeover attacks can happen when a company creates a dns entry that points to a third party service cname record however forget about the third party application leaving it vulnerable to be hijacked by another party. What is a subdomain hijack takeover vulnerability.
Sub domain creation has to go through the domain name registrar that is hosting their domain name and this administrative account with the registrar is usually has a strong well protected password that often is couple with two factor authentication. Subdomain takeover or subdomain hijacking refers to a technique by which unused subdomains can be made to point to a location of the attacker s choice. This means that a resource is being imported on the target page for example via a blob of javascript and the hacker can claim the subdomain from which the resource is being imported.
Second order subdomain takeovers what i like to refer to as broken link hijacking are vulnerable subdomains which do not necessarily belong to the target but are used to serve content on the target s website. So sub domain hijacking does not usually happen with hijacking a registrar admin account. In a hypothetical scenario an attacker could hijack one of these subdomains and host phishing pages to harvest login credentials for microsoft employees business partners or even its end users.