SIM Swap Attacks Explained: How to Detect and Prevent Them
What a SIM swap attack is, how attackers convince a carrier to move your number to their SIM, the warning signs, and the 6 settings that block the attack in 2026.
A SIM swap attack moves your phone number from your SIM to an attacker's SIM. Once they have your number, every SMS verification code goes to them. With a few high value verification codes, they take over email, then bank, then crypto. Here is how a SIM swap works, the warning signs, and the six settings that block almost all of them.
How a SIM swap works
Recon
Attacker collects personal info from people search sites, breaches, social engineering.
Impersonate
Calls the carrier or visits a store pretending to be you.
Port
Convinces the carrier to move your number to their SIM.
Lose service
Your phone shows no service. Their phone gets your number.
Reset
Triggers password resets. SMS codes flow to them.
Drain
Empties accounts. Often crypto, banking, brokerage.
Warning signs of an active SIM swap
- Your phone shows 'No service' or 'SIM not provisioned' suddenly.
- You receive a carrier notification confirming a SIM change you did not make.
- Your email starts receiving password reset emails you did not request.
- Friends say they got strange messages from your number.
- You see logins from an unfamiliar location on your accounts.
The 6 settings that block SIM swaps
Port out PIN
All major US carriers support port out PINs and account passcodes.
Move off SMS
Use TOTP (Authy, Google Authenticator) or hardware keys.
Password manager
Reused passwords accelerate SIM swap escalation.
Hardware key on email
Your primary email is the recovery point. Protect it.
Kill SMS recovery
Disable SMS recovery on email and exchanges.
Reduce exposure
Opt out of people search sites that show name + address + phone.
What a reverse phone lookup catches
A modern reverse phone lookup can flag a recent SIM swap on a number because phone intelligence providers receive the signal from carriers. This is useful if you are buying or selling a SIM linked account, verifying a counterparty, or checking your own number for irregular activity.
Run a private check on any phone number
Get a 60 second report with possible owner, line type, location signals, and risk indicators. The phone owner is not notified.
Run a checkFrequently asked questions
How common are SIM swap attacks?
The FBI's IC3 receives thousands of SIM swap complaints a year, and losses have grown to hundreds of millions of dollars. Crypto holders and high net worth individuals are the most targeted.
Can I detect a SIM swap before money is lost?
Often yes. Sudden loss of service is the leading indicator. Call your carrier from another phone immediately if it happens.
Will a port out PIN really protect me?
It blocks the simplest variant. Determined attackers may still social engineer past it, but the PIN raises the bar significantly.
Should I move all my 2FA off SMS?
Yes for any account that matters. Email, banking, crypto, work, and your password manager itself. Use TOTP or a hardware key like YubiKey.
Can a phone number checker show whether a number was SIM swapped?
Some phone intelligence providers expose a recent SIM swap signal. A reverse phone lookup may surface this on the report.
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