Tencent Cloud's number authentication product protects against SMS bombing through multiple layers of security mechanisms.
Rate Limiting and Frequency Control: The system enforces strict limits on the number of SMS requests allowed per phone number or IP address within a specific time frame. For example, if a user attempts to request SMS verification codes too frequently, the system will temporarily block further requests.
Behavioral Analysis: The product uses machine learning to detect abnormal patterns, such as rapid successive requests from the same device or IP. If suspicious behavior is identified, the system may require additional verification steps, like CAPTCHA or email confirmation, before sending an SMS.
Device and IP Reputation System: Tencent Cloud maintains a reputation database to track devices and IPs associated with malicious activities. Requests from high-risk sources are either throttled or rejected outright.
One-Time Password (OTP) Expiry and Usage Limits: SMS verification codes have a short validity period (e.g., 5 minutes) and can only be used once. Even if intercepted, the code becomes invalid after use or expiration.
Graphical Verification (CAPTCHA): For high-risk requests, the system may prompt the user to complete a CAPTCHA challenge before proceeding with SMS delivery.
Example: If an attacker tries to flood a phone number with SMS requests, the system will detect the abnormal frequency and block further attempts for a set duration, while logging the incident for further analysis.
For such scenarios, Tencent Cloud's SMS Verification and Number Authentication services provide robust protection against SMS bombing, ensuring secure and reliable user verification.