What are the loopholes in the mobile game redemption code?

Common loopholes in mobile game exchange code;

Mobile phone redemption codes are used more and more in web applications. Usually, mobile phone verification code is used for identity verification in business modules such as user login, user registration and password reset. In view of the possible problems of mobile phone verification code, I collected some cases of mobile phone verification code loopholes, and made a summary here to make my thinking clearer when testing. Common mobile phone verification code vulnerabilities are as follows:

1, invalid verification

2. Client authentication bypass

3. SMS bombing

4, verification code blasting

5. The verification code is not bound to the mobile phone number.