SIM Swap Attacks: How Hackers Hijack Your Phone to Steal Crypto

A SIM swap attack is when a criminal takes control of your mobile phone number by getting your carrier to transfer it to a SIM card they control. With your number, they receive your text-message login codes and password-reset links, and can break into crypto exchange, email and social media accounts within minutes.

Crypto holders are attractive targets because stolen crypto is fast to move and hard to recover. People who talk publicly about their holdings are at particular risk. The good news is that a few changes to how you secure accounts make SIM swaps far less dangerous.

How a SIM Swap Attack Works

1. 1Research. The attacker gathers personal details — name, address, date of birth, phone number — from data breaches, social media or phishing.
2. 2Carrier takeover. They contact your mobile carrier pretending to be you, claim a lost or broken phone, and request a new SIM. Some attacks involve bribed insiders or compromised carrier accounts.
3. 3Number transfer. Your number moves to their SIM. Your phone loses service.
4. 4Account resets. They request password resets for your email and exchange accounts, receive the codes by text, and log in.
5. 5Theft. They change your security settings, withdraw crypto to their own wallets and sometimes post scams from your social accounts.

The whole process can take less than an hour. High-profile accounts have been hit too: in January 2024, the US Securities and Exchange Commission said an unauthorized party had taken control of the phone number linked to its X account in an apparent SIM swap, then used the account to post a false announcement.

What Attackers Can and Cannot Do

This is why the main defense is to stop your phone number from being the key to your accounts.

Warning Signs You May Be a Victim

• Your phone suddenly shows no service or emergency-only mode while Wi-Fi still works.
• You receive unexpected texts or emails about SIM changes, port requests or password resets.
• You are logged out of accounts or apps without explanation.
• Friends tell you they received strange messages from you.

If you see these signs, act immediately — minutes matter.

How to Protect Yourself From SIM Swaps

Fix your two-factor authentication

1. 1Switch from SMS to an authenticator app or hardware security key on exchanges, email and any account linked to money. Our guide to two-factor authentication for crypto accounts compares the options.
2. 2Remove your phone number as a recovery method wherever the service allows it.
3. 3Store backup codes offline, not in your email.

Harden your mobile account

• Ask your carrier for a port-out PIN, account PIN or SIM lock. Names and options differ by carrier and country.
• Use a unique, strong password for your carrier's online account.
• Ask whether the carrier offers extra verification for SIM changes.

Reduce your exposure

• Do not publicly share how much crypto you hold.
• Use a separate, private phone number or email for financial accounts if practical.
• Lock down social media profiles that reveal your birthday, address or phone number.

Keep long-term holdings in self-custody

Funds on an exchange are only as safe as your exchange login. Long-term savings in a hardware wallet are not reachable through your phone number. See how to secure your exchange account for exchange-specific settings.

Common Myths About SIM Swaps

• "My carrier would never fall for it." Attackers use stolen personal data, social engineering and sometimes insiders. Carriers have improved safeguards, but no system is perfect.
• "I'm not famous enough to be targeted." Many victims are ordinary people whose phone numbers appeared in a data breach or a crypto-related forum.
• "I use 2FA, so I'm safe." If that 2FA is SMS-based, a SIM swap defeats it.
• "A strong password is enough." Password resets by text message bypass even the strongest password.

What to Do If You Are SIM Swapped

1. 1Call your carrier from another phone and report the fraud. Ask them to restore your number and lock the account.
2. 2Secure your email first, since it controls password resets elsewhere. Change passwords and sign out other sessions.
3. 3Contact your exchanges to freeze accounts and withdrawals.
4. 4Change passwords and 2FA on all financial accounts.
5. 5Warn your contacts that messages from your number or social accounts may be fraudulent.
6. 6Report the crime to the police and any relevant cybercrime authority, and keep records. Our guide to what to do if your wallet is compromised covers related steps.

Be wary of anyone who contacts you afterward offering to recover your crypto for a fee — that is a common follow-up scam. Once your accounts are secure again, review every security setting you changed in a hurry, and write down which recovery methods each account now uses so you are not caught out the next time.

Bottom line

SIM swap attacks exploit the fact that many accounts treat your phone number as proof of identity. Remove that weakness: move from SMS to an authenticator app or security key, lock down your carrier account, limit what you share publicly and keep savings in self-custody. Then a hijacked number becomes an inconvenience rather than a disaster. For more defenses, browse our security guides.