Definition
Homoglyph
A homoglyph is a character from another alphabet drawn identically to a Latin letter, used to register a domain name visually indistinguishable from a real company's.
The Cyrillic “а” (U+0430) and the Latin “a” (U+0061) are two different characters that render exactly the same. A domain that swaps one for the other is, to the eye, yours. To a computer it is an entirely separate domain, which a fraudster can buy and configure in ten minutes.
DNS encodes these characters as punycode, prefixed with xn--: the deceptive domain becomes something like xn--exmple-9wa.com. Modern browsers often display that form as a warning; mail clients much less often.
- Also known as
- homoglyph, homograph attack, IDN homograph, punycode, Cyrillic lookalike