If you are asked to send an SMS when you go to a Yandex site or a social network, you have most likely encountered a phishing virus. To find out more about what this is and what you should do in this situation, see the section Phishing.
There may be cases when a tab opens with an offer to update Yandex.Browser to the latest version, but the site address looks suspicious. We do not recommend following the update instructions on pages like this. These are fraudulent websites, created in order to get you to send a fee-based SMS under any pretext.
For more information, see the section SMS fraud warning.