Preventing SIM swap takeovers of exchange accounts: protective steps for South African users

A SIM swap happens when someone persuades or tricks a mobile network into moving your number to a SIM card they control. From that moment, calls and text messages meant for you go to them, including the one-time codes many services send for logins, password resets and withdrawals. Crypto accounts are an attractive target because transfers are fast and hard to reverse. The good news is that you can make a swap much less useful to an attacker, and sometimes harder to carry out at all. This guide describes preventive steps for South African users: what to ask your network, how to move Binance, OKX, Bybit or Bitget accounts away from SMS, and how to react quickly if your phone suddenly loses signal.

Make the number harder to move

Contact your mobile network through its official channels and ask what protection it offers against unauthorised SIM swaps or number porting on your account, such as additional verification, a security PIN or a requirement to visit a store in person. Options vary between providers, so ask directly rather than assuming. Keep your account details with the network up to date. Avoid publishing your phone number on social media or in public groups, since attackers often start by linking a number to a name and a crypto interest.

Remove SMS as the only gatekeeper

On each exchange, switch the main second factor from SMS to an authenticator app or a passkey where supported, and keep SMS only as an additional option if the platform requires it. Do the same on the email account linked to the exchange, because email resets are a common next step after a swap. Store the authenticator backup key on paper in a safe place. Once SMS is no longer the deciding factor, a swapped number alone is not enough to take over the account.

Add friction to withdrawals

Turn on the withdrawal address allowlist offered by the exchange so funds can only go to destinations you have saved and verified. Set up an anti-phishing code for emails and enable alerts for logins, security changes and withdrawals. Many platforms apply a waiting period after security settings are changed; read the help centre to understand how this works on your exchange, because it is exactly the delay that gives you time to react if someone changes your settings.

Know the warning signs and act fast

If your phone suddenly shows no service in a place where it normally works, or you receive a message about a SIM change you did not request, treat it as urgent. Call your network from another phone to ask whether your number has been moved. Sign in to your email and exchange accounts from a trusted device, check recent security activity and change passwords. If you see changes you did not make, contact each exchange's support through its official help centre straight away and ask about temporarily restricting the account.

Risk boundary: South Africa Crypto Guide

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Scenario checkpoint

• Ask your mobile network which protections against unauthorised SIM swaps it offers.
• Replace SMS with an authenticator app or passkey as the main second factor on each exchange.
• Protect the email linked to your exchange with a factor that does not depend on SMS.
• Turn on the withdrawal allowlist and alerts for logins, security changes and withdrawals.
• Call your network from another phone at once if your signal drops without explanation.