How the Scam Works?
If cybercriminals have your telephone number, they can install WhatsApp on a new phone and initiate the registration process using your telephone number. Once the registration process has started, WhatsApp will send a randomly generated six-digit code in a text message(SMS) to your phone number. This code is like a temporary password for gaining access to your WhatsApp account.
Next, the cybercriminals will send a text message to your phone with a message claiming the sender is your cellphone provider or some other organization. The message will instruct you to forward the six-digit code you have received, which was initiated by the cybercriminals' registration process. If you send them the code, the cybercriminals will enter it in the WhatsApp they have installed and registered with your telephone number on the new phone. Once this is done, you will be signed out of WhatsApp on your phone because the cybercriminals have signed into your account from their new phone. With access to your account, the cybercriminals will send spam, scam and other malicious messages to your contacts in an attempt to scam them or take control of their WhatsApp accounts.
How to Take Back Control of Your WhatsApp Account?
Go back to WhatsApp on your phone and re-register. After re-registering, WhatsApp will send you a new verification code via text message to your phone. After receiving the code, enter it in WhatsApp. WhatsApp will then sign you back into your account and sign out the cybercriminals. Now, check your WhatsApp account to see if the cybercriminals have sent messages to your contact. If they did, delete the messages and tell your friends your account was hacked.
Never forward text messages with security codes to anyone. These codes are like passwords for gaining access to your online accounts. Therefore, just like your passwords, do not give them to anyone.