Account takeover
Definition
When someone other than the owner gains control of an online account, usually by stealing a password or login code.
Account takeover, explained
Account takeover, often shortened to ATO, is when an attacker gets into your account and locks you out or uses it for their own purposes. Common routes include reused passwords leaked from another site, phishing pages, smishing texts that trick you into sharing a verification code, SIM swaps that redirect your SMS codes, and recycled phone numbers that still receive texts meant for a previous owner. Once inside, attackers may change the email and phone on the account, message your contacts, make purchases or sell the account. Protecting yourself comes down to a few habits: use a unique password for each account with a password manager, turn on two-factor authentication with an authenticator app or passkey where possible, never share a code with anyone who contacts you, and keep your recovery email and phone up to date. If you signed up with a temporary number, replace it with a method you control, because a recycled number is a weak point. Act quickly if you see login alerts you do not recognize.
Related terms
SIM swap
An attack where someone gets your carrier to move your number to their SIM so they receive your calls and codes.
Smishing
Phishing by text message: a fake SMS that tries to get you to click a link, share a code or send money.
2FA (two-factor authentication)
Signing in with two different proofs, typically a password plus a code, app prompt, passkey or security key.
Where you'll meet this term
How to Receive SMS Online: Get Verification Codes Without Your Own Number
How to receive SMS verification codes online: free public inboxes vs private rented numbers vs VoIP apps vs a second SIM, with risks and setup steps.
Read the guide →Safety & privacyHow to Protect Your Phone Number From Spam, Data Brokers and SIM Swaps
Your phone number links to spam, data brokers, SIM-swap attacks and account takeover. Practical steps to protect it, and where a temporary number helps.
Read the guide →