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An SSL certificate, now more accurately called a TLS certificate, proves that a website is who it claims to be and lets browsers encrypt traffic to it. Certificates are issued by certificate authorities (CAs), which check that the requester controls the domain before issuing one.

What a certificate does

The certificate proves the website’s identity, much like an ID card. Visitors rely on this before they type in a password or a card number.

What Telivy checks

Telivy checks the certificates on the company’s domains and subdomains and raises a finding for each problem below.
An expired certificate makes browsers show a warning, and many visitors leave. It can also make it easier to intercept traffic with a man-in-the-middle attack. Automatic renewal helps, but someone still has to set it up and watch that it works.Telivy flags certificates that have expired or expire within 30 days.
A self-signed certificate wasn’t issued by a trusted CA, so browsers don’t trust it and show visitors a security warning.Telivy flags self-signed certificates as a Medium severity finding.
Certificates signed with MD5 or SHA-1 are open to collision attacks, which can let an attacker forge a certificate and impersonate the site. Weak algorithms can also fail compliance requirements.Telivy flags any certificate on the company’s domains and subdomains that is signed with a weak algorithm.
Browsers trust a certificate through a chain: a root CA such as Let’s Encrypt or DigiCert signs an intermediate certificate, which signs the website’s certificate. If the issuer (usually the intermediate) can’t be found, the chain breaks, the browser can’t verify the certificate, and visitors see a warning.Telivy flags certificates whose issuer can’t be found.
A long validity period means fewer renewals, but it also gives attackers more time to exploit a weakness in the algorithm or a leaked private key. Browsers increasingly distrust certificates that are valid for longer than the industry standard.Telivy flags certificates with a longer validity period than usual and shows the details in the finding.