ZeroSSL GmbH

ZeroSSL GmbH is a publicly trusted intermediate certificate authority operated by ZeroSSL (apilayer GmbH) and chained to USERTrust RSA Certification Authority. It is recognized by all mainstream browsers and operating system trust stores, so the certificate itself is not a phishing indicator - the same intermediate signs millions of legitimate sites. phishunt only flags the specific domains listed below as suspicious; ZeroSSL GmbH as a CA is fine.

Yes. ZeroSSL GmbH is a publicly trusted intermediate CA operated by ZeroSSL (apilayer GmbH), included in the Microsoft, Apple, Google and Mozilla root trust stores. Every mainstream browser automatically accepts certificates it signs. The intermediate itself is not a phishing signal — what matters is the specific domain. phishunt flags only the suspicious domains listed below; ZeroSSL GmbH keeps signing millions of legitimate sites.

ZeroSSL GmbH is operated by ZeroSSL (apilayer GmbH). It is a RSA & ECDSA intermediate that chains up to the USERTrust RSA Certification Authority root, which ZeroSSL (apilayer GmbH) also owns. Anyone can look up the chain in the public Certificate Transparency logs; the same operator publishes a Certificate Policy / Certification Practice Statement (CP/CPS) describing how issuance and revocation work.

When a browser shows ZeroSSL GmbH as the certificate issuer for a site, it means TLS was validated through ZeroSSL (apilayer GmbH)'s RSA & ECDSA chain ending at USERTrust RSA Certification Authority. That is normal for tens of millions of legitimate sites that use ZeroSSL (apilayer GmbH)'s automated DV TLS. The certificate proves the connection is encrypted and that the certificate matches the hostname — it does not prove the site behind it is trustworthy. Always verify the domain name itself.

ZeroSSL (apilayer GmbH) issues RSA & ECDSA domain-validated certificates automatically and at no cost (or very low cost), which is the exact workflow scammers need to put HTTPS on a throwaway domain. Domain validation only proves that the requester controls the domain name, not that the site behind it is trustworthy. phishunt lists the specific domains currently flagged below — those are the suspicious ones, not ZeroSSL GmbH itself.

In a desktop browser, click the padlock in the address bar and open the certificate viewer. Confirm the issuer chain ends at USERTrust RSA Certification Authority, that the subject matches the domain you expect, and that the notAfter date has not passed. A valid ZeroSSL GmbH certificate only proves TLS was negotiated correctly — always verify the domain name itself belongs to the service you intended to visit.

ZeroSSL GmbH and its siblings (ZeroSSL ECC Domain Secure Site CA, ZeroSSL RSA Domain Secure Site CA) share the same operator (ZeroSSL (apilayer GmbH)) and roll up to the same root (USERTrust RSA Certification Authority). CAs rotate multiple intermediates so that if one key ever has to be revoked, the damage is contained. As a user, you can treat all of them as the same trust anchor.