We are used to the fact that the main purpose of a SIM card and an operator is to provide voice calls, SMS and mobile Internet, however, various services have assigned another important function to the operators – to act as an intermediary to confirm the identity of the client.
Seriously, remember how much is tied to your phone number right now. Authorization in the Internet bank, transfers by phone number, order confirmation, and even an account on State Services. In addition, now the balance of your number is gradually turning into a means of paying for services, which is also an additional 'load' on the number.
It would seem, what's wrong here? Confirmation by phone number is a simple and straightforward procedure that excludes the use of fake data and guarantees additional security for the same banking services.
All this is true, if not for one 'but'. The SIM is becoming a security bottleneck. I will give a simple example: several times I saw situations when, when replacing a SIM-card, consultants in some clever way gave the client a non-working dummy, and they themselves got access to the Internet bank using the replaced SIM card and made transfers from the client's account … because they were confirmed by a short SMS password!
And if your bag is stolen with a bank card and a SIM card, then this is a complete nightmare, because in order to steal money from the card, in addition to the card number and CVV code, you will need the same short SMS code. Therefore, if you suddenly encounter such a problem, first of all, block the SIM card either by calling the operator, or order a replacement in the operator's salon.
However, banks and operators are also aware of the fact that now many services are tied to the client's number, so they introduce additional security measures. For example, in Tinkoff Bank (I only came across this with them, but I heard that some banks do this too), when you replace the SIM card, you will be asked to re-confirm your identity by phone. The fact is that each physical SIM card has its own unique IMSI number, the bank sees when it changes and simply blocks the receipt of short codes. You can restore the shipment by calling the support service.
In my opinion, now the SIM-card is becoming the very authorization key, losing which, you will find yourself in a very vulnerable situation. Therefore, if something happened to the SIM card, immediately block it and go change it to the operator's salon.