Analyse domain's SSL (HTTPS) certificates and test host's SSL connection and configuration.

An SSL (Secure Sockets Layer) certificate is a digital certificate that authenticates the identity of a website and encrypts information sent to the server using SSL technology. A certificate serves as an electronic "passport" that establishes an online entity's credentials. When user attempts to send confidential information to a web server, his browser accesses the server's digital certificate and establishes a secure connection. Traffic between the browser and the host is transferred in an undecipherable format that can only be decrypted with the proper key.

Read more:

• Certificate authority
• Transport layer security
• Public key certificate

Detailed information about the certificate. The test is tagged with a Failed if no certificates were found for the domain.

Uniquely identifies the certificate within Certificate Authority (CA) systems to track revocation information.

List of the allowed purposes the certificate can be used for.

List of the allowed purposes the certificate can be used for when acting as a Certificate Authority.

The algorithm used to sign the public key certificate.

Information regarding certificate's public key.

Shows an ordered list of all the certificates in the chain, enabling the receiver to verify that the sender is trustworthy. Each certificate in the chain is signed by the entity identified by the next certificate in the chain. The signatures of all certificates in the chain must be verified up to the Root CA Certificate.

Who the Server's (SSL) certificate is issued to.

Who the certificate was issued by.

Check date and time since when the certificate is valid. Compare the Not valid before field with the current date and time.

Check date and time until the certificate is valid. Compare the Not valid after field with the current date and time.

Request the CRL (Certificate revocation list) provided by the certificate's issuer and check if the SSL certificate is present there.

Check if the SSL certificate is revoked with the use of OCSP (Online Certificate Status Protocol).

OCSP is an Internet protocol used for obtaining the revocation status of an X.509 digital certificate. It is described in RFC 6960 and is on the Internet standards track. It was created as an alternative to CRL (Certificate Revocation Lists), specifically addressing certain problems associated with using CRLs in a PKI (Public Key Infrastructure).

Check if the target domain name is referenced in the SSL certificate's Common Name or Subject Alternative Names fields.

Check for the common SSL certificate's and the host's SSL configuration vulnerabilities.

Check if the certificate was issued by the target website itself and wasn't verified by a trusted Certificate Authority. While self-signed SSL certificates still encrypt connection, most web browsers display a security alert. Self-signed certificates are often used by malware or vulnerable hosts. Unlike the most CA-issued certificates, self-signed certificates are free.

Check if the host supports deprecated or vulnerable SSL protocols.

Check if the host supports suboptimal cipher suites.

Check SSL connection compression methods enabled by the host.

Check if HPKP headers are set in the host's response.

HTTP Public Key Pinning (HPKP) is a security mechanism delivered via an HTTP header which allows HTTPS websites to resist impersonation by attackers using mis-issued or fraudulent certificates. Now the mechanism is considered to be deprecated and even insecure. It's not recommended to be used anymore

Check if HSTS header is returned by the host.

HTTP Strict Transport Security (HSTS) is a web security policy mechanism which helps to protect websites against protocol downgrade attacks and cookie hijacking. It allows web servers to declare that web browsers (or other complying user agents) should only interact with it using secure HTTPS connections, and never via the insecure HTTP protocol. HSTS is on the IETF standards track. It's specified in RFC 6797.

Check if the host's OpenSSL version installed is fixed against the Heartbleed Bug. This is a serious vulnerability in the popular OpenSSL cryptographic software library. This weakness allows stealing information protected, under normal conditions, by the SSL/TLS encryption.

Check if TLS_FALLBACK_SCSV is supported by the host - to protect against POODLE attacks.

TLS_FALLBACK_SCSV is recommended for a client to indicate that it is knowingly repeating a SSL/TLS connection attempt over a lower protocol version it supports because the last one has failed for some reason. When the server sees a TLS_FALLBACK_SCSV signal it compares the highest protocol version it supports to the version indicated in the Client Hello. If the client's version is lower, the server responds with a new Alert defined by the RFC as inappropriate_fallback. The idea is that the server knows the client supports something better so the connection should have negotiated that. The inappropriate_fallback Alert is a “fatal” error, i.e. the SSL/TLS connection is aborted.

Check if the TLSA record is correctly configured for the domain name.

This is a part of DNS-based authentication of named entities: RFC 6698. DNS-based Authentication of Named Entities (DANE) is a protocol to allow X.509 certificates, commonly used for Transport Layer Security (TLS), to be bound to DNS names using Domain Name System Security Extensions (DNSSEC).

Check if the certificate's public key is present in the Debian blacklist.

Check if OCSP Stapling is enabled, analyse it's response in order to check the SSL certificate's validity.

The Online Certificate Status Protocol (OCSP) is used for obtaining the revocation status of an X.509 digital certificate. It's on the Internet standards track: RFC 6960. It was created as an alternative to Certificate Revocation Lists (CRL), specifically addressing certain problems associated with using CRLs in a public key infrastructure (PKI). Messages communicated via OCSP are encoded in ASN.1 and are usually communicated over HTTP.