DNS

WHOIS is the public directory of domain registration data, showing details like the registrar, creation date, and, where not redacted, the registrant, used to investigate and report abusive domains.

Domain hijacking is the theft of control over a domain, by compromising the owner registrar account, transferring it without authorization, or altering its DNS, so the attacker can redirect or impersonate the real site.

A subdomain takeover is when an attacker claims a subdomain you no longer use but still point to a third-party service, letting them host content on your real domain.

Domain monitoring is the continuous tracking of newly registered and changed domains that resemble your brand, so you can spot lookalikes and abuse early, before they are used against you.

Punycode is the encoding that represents non-ASCII characters in domain names using only ASCII, turning an internationalized domain into a string that starts with "xn--". Attackers exploit it to hide homoglyph domains.

Domain reputation is a score that mail providers, browsers, and security tools assign to a domain based on its history, deciding whether to trust, flag, or block its mail and links.

Bitsquatting is registering domains one bit different from a target domain, exploiting rare memory errors that flip a single bit so a device resolves the wrong, attacker-owned name.