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Vol. 1 · Ed. 2026
CyberGlossary
Entry № 536

Homograph Attack (IDN Homograph)

Что такое Homograph Attack (IDN Homograph)?

Homograph Attack (IDN Homograph)A phishing technique that registers a domain using Unicode characters visually identical to ASCII ones — Cyrillic 'а' for Latin 'a', Greek omicron for Latin 'o' — so the attacker URL is indistinguishable from the legitimate one to the eye.


A homograph attack — formally an Internationalized Domain Name (IDN) homograph attack — abuses the visual similarity between characters across Unicode scripts. The domain `аpple.com` looks identical to `apple.com` in most fonts, but the leading 'а' is Cyrillic U+0430, not Latin U+0061; the punycode form is `xn--pple-43d.com`. Attackers register such lookalikes for phishing landing pages, malware delivery, and consent-phishing OAuth applications. Browsers and registrars have introduced mitigations: most TLDs restrict mixed-script registrations, Chrome/Firefox show punycode when a label mixes scripts or uses 'similar' Unicode, and DNS resolvers and email gateways flag IDN domains. Attackers have responded with single-script Cyrillic-only or Greek-only domains that bypass mixed-script checks, and with subdomain tricks (`paypal.com.attacker.xn--…`). Defenses combine browser punycode display, certificate-transparency monitoring for lookalike registrations, DMARC + brand-monitoring services, and user training that hovering over the URL reveals the real registered name.

Примеры

  1. 01

    An attacker registers `аррӏе.com` (Cyrillic а, р, ӏ, е) and serves an Apple ID phishing page with a valid Let's Encrypt certificate for the punycode form.

  2. 02

    A brand-protection feed monitors Certificate Transparency for newly issued certs that visually resemble the client's domain across the Unicode confusables table.

Частые вопросы

Что такое Homograph Attack (IDN Homograph)?

A phishing technique that registers a domain using Unicode characters visually identical to ASCII ones — Cyrillic 'а' for Latin 'a', Greek omicron for Latin 'o' — so the attacker URL is indistinguishable from the legitimate one to the eye. Относится к категории Атаки и угрозы в кибербезопасности.

Что означает Homograph Attack (IDN Homograph)?

A phishing technique that registers a domain using Unicode characters visually identical to ASCII ones — Cyrillic 'а' for Latin 'a', Greek omicron for Latin 'o' — so the attacker URL is indistinguishable from the legitimate one to the eye.

Как работает Homograph Attack (IDN Homograph)?

A homograph attack — formally an Internationalized Domain Name (IDN) homograph attack — abuses the visual similarity between characters across Unicode scripts. The domain `аpple.com` looks identical to `apple.com` in most fonts, but the leading 'а' is Cyrillic U+0430, not Latin U+0061; the punycode form is `xn--pple-43d.com`. Attackers register such lookalikes for phishing landing pages, malware delivery, and consent-phishing OAuth applications. Browsers and registrars have introduced mitigations: most TLDs restrict mixed-script registrations, Chrome/Firefox show punycode when a label mixes scripts or uses 'similar' Unicode, and DNS resolvers and email gateways flag IDN domains. Attackers have responded with single-script Cyrillic-only or Greek-only domains that bypass mixed-script checks, and with subdomain tricks (`paypal.com.attacker.xn--…`). Defenses combine browser punycode display, certificate-transparency monitoring for lookalike registrations, DMARC + brand-monitoring services, and user training that hovering over the URL reveals the real registered name.

Как защититься от Homograph Attack (IDN Homograph)?

Защита от Homograph Attack (IDN Homograph) обычно сочетает технические меры и операционные практики, как описано в определении выше.

Какие есть другие названия Homograph Attack (IDN Homograph)?

Распространённые альтернативные названия: IDN homograph attack, Unicode lookalike domain.

Связанные термины

См. также