How to Protect Against SIM-Swap Attacks on Exchanges

A SIM-swap attack happens when a criminal convinces your mobile carrier to transfer your phone number to a device they control. Once they have your number, they can intercept SMS verification codes and reset passwords, potentially taking over your crypto exchange account. These attacks have caused some of the largest individual crypto losses on record.

This guide explains how SIM swaps work, why SMS-based security is vulnerable, and the concrete steps you can take to protect your accounts even if your phone number is compromised.

Why SMS Is Vulnerable

SMS codes feel convenient, but they depend on your carrier's security and can be redirected to an attacker's device through social engineering. If SMS is your only second factor, controlling your number can be enough to seize your account.

• Carriers can be tricked into porting your number.
• SMS codes can be intercepted once the number is moved.
• Password resets often rely on SMS verification.
• SMS offers no protection against phishing.

Stronger Alternatives

Replace SMS with app-based authenticators or, better still, hardware security keys and passkeys. These methods are tied to a device you physically control, so moving your phone number does nothing to help an attacker.

Hardening Your Carrier Account

Ask your carrier to add a port-out PIN or account lock, avoid sharing your number publicly, and remove SMS as a recovery option wherever a stronger alternative exists. Layering these defenses makes a SIM swap far less damaging even if it succeeds.

Conclusion

SIM-swap attacks exploit the weakest link in many security setups: a phone number. By moving away from SMS-based authentication, adding a carrier port-out lock, and relying on app-based or hardware authentication, you remove the payoff for attackers. Take these steps now, before an attack, and your exchange account will be far better protected against account takeover.