An unauthorized SIM change, commonly known as a SIM swap, is a type of fraud in which an attacker gains control of a victim's phone number by transferring it to a new SIM card. This allows the attacker to intercept calls, messages, and authentication codes, granting them access to sensitive accounts such as banking, email, and social media.
How Does Fraudulent SIM Swapping Work?
Fraudsters typically execute a SIM swap attack through the following steps:
Gathering Personal Information – Attackers collect personal data about the victim through phishing, data breaches, social engineering, or other means.
Contacting the Mobile Carrier – The fraudster impersonates the victim and contacts the mobile carrier, claiming a lost or stolen SIM card and requesting a transfer to a new one.
Bypassing Security Checks – The attacker may use stolen data to answer security questions or manipulate customer service representatives to approve the SIM change.
Activating the New SIM Card – Once the carrier transfers the number to the new SIM card, the attacker gains control of the victim’s phone number.
Intercepting Sensitive Data – The fraudster can now receive calls, text messages, and one-time passwords (OTPs), which are often used for two-factor authentication (2FA). This enables access to bank accounts, social media, email, and other critical services.
How to Protect Against SIM Swap Attacks
To safeguard against fraudulent SIM swaps, consider the following measures:
Enable SIM Lock – Set up a PIN for your SIM card to prevent unauthorized transfers.
Use Strong Authentication – Opt for app-based authentication (e.g., Google Authenticator, Authy) instead of SMS-based 2FA.
Set Up a Carrier PIN or Passcode – Many carriers offer additional security layers such as requiring a PIN or passcode before making account changes.
Monitor Account Activity – Regularly check your mobile carrier account for unauthorized changes.
Be Cautious of Phishing Attempts – Avoid clicking on suspicious links or sharing personal information over the phone, email, or text messages.
Enable Account Alerts – Set up notifications for login attempts and changes to sensitive accounts.
Consider a Separate Number for Banking – Use a different phone number, not widely shared, for financial transactions and sensitive services.
By taking proactive steps, individuals can minimize the risk of falling victim to SIM swap fraud and protect their digital identities.