Let's Encrypt

Let's Encrypt is a publicly trusted intermediate certificate authority operated by Internet Security Research Group (ISRG) and chained to ISRG Root X1, ISRG Root X2. 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; Let's Encrypt as a CA is fine.

Yes. Let's Encrypt is a publicly trusted intermediate CA operated by Internet Security Research Group (ISRG), 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; Let's Encrypt keeps signing millions of legitimate sites.

Let's Encrypt is operated by Internet Security Research Group (ISRG). It is a RSA & ECDSA intermediate that chains up to the ISRG Root X1, ISRG Root X2 root, which Internet Security Research Group (ISRG) 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 Let's Encrypt as the certificate issuer for a site, it means TLS was validated through Internet Security Research Group (ISRG)'s RSA & ECDSA chain ending at ISRG Root X1, ISRG Root X2. That is normal for tens of millions of legitimate sites that use Internet Security Research Group (ISRG)'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.

Internet Security Research Group (ISRG) 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 Let's Encrypt itself.

In a desktop browser, click the padlock in the address bar and open the certificate viewer. Confirm the issuer chain ends at ISRG Root X1, ISRG Root X2, that the subject matches the domain you expect, and that the notAfter date has not passed. A valid Let's Encrypt certificate only proves TLS was negotiated correctly — always verify the domain name itself belongs to the service you intended to visit.

Let's Encrypt and its siblings (R3, R10, R11, R12) share the same operator (Internet Security Research Group (ISRG)) and roll up to the same root (ISRG Root X1, ISRG Root X2). 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.