A doppelganger domain is a domain spelled identical to a legitimate fully qualified domain name (FQDN) but missing the dot between host/subdomain and domain, to be used for malicious purposes.

Overview

Typosquatting's traditional attack vector is through the web to distribute malware or harvest credentials. Other vectors such as email and remote access services such as SSH, RDP, and VPN also can be leveraged. In a whitepaper by Godai Group on doppelganger domains, they demonstrated that numerous emails can be harvested without anyone noticing.^[1]

Example

For email address "ktrout@fi­nance.corpu­dyne.com", the doppel­ganger domain would be "finance­corpu­dyne.com"; hence, an email acci­den­tally addressed to "ktrout@financecorpudyne.com" (i.e. with the dot between "finance" and "corpu­dyne" having acci­den­tally been omitted) would go to the doppel­ganger domain rather than to the legitimate user.