Protection against untrusted certificates

Yandex Browser for Mobile checks site certificates. The browser will warn you if the website cannot provide secure encryption of your data due to problems with the certificate.

  1. Why websites need a certificate
  2. What makes an untrusted certificate dangerous
  3. Block websites with untrusted certificates
  4. Reasons for blocking

Why websites need a certificate

Your personal data and payment information should be protected when you send them to a website. Websites use the HTTPS protocol for secure connection. The protocol activates an asymmetric encryption algorithm, where data is encrypted with a public key and decrypted with a private key. For each session, the browser regenerates the private key and transmits it to the website in addition to taking precautionary measures to prevent theft.

However, if you end up on a phishing website, it might get the private key and then decrypt your data. To protect against phishing, websites use digital certificates issued by special certification authorities. The certificate guarantees that the encryption keys actually belong to the website owner.

What makes an untrusted certificate dangerous

You may end up on a phishing website, or your data will not get the necessary protection on the original website (for example, if the website's certificate has expired). As a result, hackers can:

  • Intercept or replace your personal data, and read your correspondence.
  • Get your payment data (card number, holder's name, expiry date and CVV2) and use it to steal money from your account.

Block websites with untrusted certificates

If the site cannot provide secure encryption due to problems with the certificate, the icon appears on the left side of the SmartBox, and you will see the following warning:

“Cannot establish a secure connection. Hackers may try to steal your data (such as passwords, messages or your bank card number) ”.

You can either choose not to visit the website, or add the certificate to the trusted list by tapping Details in the dialog box, and then Make an exception for this site. The certificate will be on the trusted list for 30 days, and then you will have to make an exception for it again.

Attention. Tap Make an exception for this website only if you’re sure the certificate is trustworthy. Otherwise hackers can get access to your personal data!

Reasons for blocking

Yandex Browser blocks websites that have the following problems with certificates:

The certificate author is unknown

The certificate might have been installed by a hacker or special software. Ad blockers and similar applications may replace website certificates with their own. If the certificate was installed by an application, you need to find it and disable checking HTTPS in it.

You can also decide to trust your data to this certificate, but be aware of two potential dangers:

  • Your data may become available to unknown application developers.
  • The certificate may be installed by malware pretending to be the application. Modern browsers do not know how to verify the authenticity of certificates installed by special applications.
Incorrect site address
The website's security certificate refers to another website. The server may be incorrectly configured, but there is a probability that you have ended up on a phishing website. If this is the case, hackers can intercept your data.
Self-signed certificate

The site certificate is issued by the site itself, rather than by a certification authority. To find out more, see Self-signed certificate. Malware or hackers can intercept your data.

Untrusted root certificate
The authority that signed the certificate is not trusted. Malware or hackers can intercept your data. For more on root certificates, see the article Root Certificate.
The certificate has expired
The data that is sent will not be encrypted, which means that hackers can intercept it.
Certificate has been revoked
The site's certificate was compromised and revoked. The data that is sent will not be encrypted, which means that hackers can intercept it.
Outdated encryption
The server uses an outdated, untrustworthy encryption algorithm. Hackers can intercept your data.
Ciphers are not supported
An HTTPS connection cannot be established, because the website uses ciphers not supported by the browser. The data that is sent will not be encrypted, which means that hackers can intercept it.
The certificate key does not match the pinned key

The certificate key does not match the pinned website key. Hackers may try to replace the root certificate. Then they can intercept your data. To find out more about pinning (linking) a key, see HTTP Public Key Pinning.

Data can not be encrypted over HSTS
The browser could not enable encryption and broke the connection. The server where the website is located normally uses encryption, since the HSTS protocol is enabled on it. Lack of encryption may be a sign of a hacker attack. In this case, hackers or malware can intercept your data.