SIM Swapping: How the Attack Works and How to Stop It
In a SIM swap attack, a criminal convinces your mobile carrier to move your number to a SIM they control. They then receive your calls and texts, including verification codes.
How it happens
- Attackers gather personal details from breaches and social media.
- They contact your carrier pretending to be you, or bribe an insider.
- Your number moves to their SIM and your phone loses service.
Warning signs
- Sudden loss of mobile signal with no explanation.
- Notifications about account changes you did not make.
- Failed logins because codes are not arriving.
How to protect yourself
- Add a PIN or passcode to your mobile account.
- Ask the carrier for a number-lock or port-out protection feature.
- Use authenticator apps or security keys instead of SMS codes.
- Limit how much personal information you share publicly.
If it happens
Contact your carrier immediately, then secure your email, banking and other accounts from another device. Report the incident to your bank.
Key takeaway: SMS codes are the weak point. Move important accounts to an authenticator app or hardware key and lock down your carrier account.
