Overview and Function
Punycode is a representation system for converting Unicode characters into a limited ASCII character set used in domain name systems (DNS). It supports the Internationalized Domain Names (IDN) standard, allowing non-Latin script domains (e.g., Cyrillic, Chinese, Arabic). However, it inherently enables a homograph attack vector, where visually similar characters from different alphabets are used to mimic trusted domains. A classic case involves substituting Latin characters with nearly identical Cyrillic counterparts, such as replacing “google.com” with “gооglе.com”, where the Cyrillic ‘о’ and ‘е’ appear indistinguishable from their Latin equivalents.
Technical Breakdown of Exploit
Once registered, the deceptive domain is encoded into ASCII using the Punycode format (e.g., xn--ggl-6ncd52d.com) and functions normally within DNS infrastructure. To the user, however, the browser may still render the Unicode form depending on the browser settings and the mix of scripts used. If the domain contains exclusively one script (e.g., all Cyrillic), most modern browsers render the Unicode
