Picture the scene: you are out in town, you want to call someone, but your phone shows "No Signal". You think it is a network problem or that you forgot to pay your bill. You wait another hour, restart it, but nothing changes. In reality, at that very moment, someone has just stolen your digital identity.
This attack is called SIM Swapping (replacing the SIM card) and it is one of the most devastating fraud methods of 2026. At Altanet Craiova we want you to know exactly what to do if it happens to you, because every minute counts.
What is SIM Swapping and how is it possible?
Your phone number has become, without your wanting it, the key to all your accounts. When you want to change your Facebook password, where do you get the code? By SMS. When you make an online payment, where does the confirmation come? By SMS. Hackers know this.
SIM Swapping does not mean someone physically steals your phone from your pocket. It means a hacker convinces your mobile carrier (Orange, Vodafone, Digi, etc.) that he is "you".
How the attack unfolds (Step by step)
It is simpler than you think and relies on social engineering, not viruses:
- Data collection: The hacker finds out your full name, date of birth and address (usually from old data leaks or from Facebook).
- The call to the carrier: He calls your carrier's customer service and says: "Hello, I lost my phone and I need to move my number to a new SIM card, which I already have in my hand".
- The trick: Using your personal data, he answers the carrier's security questions. If the support agent is fooled, they activate your number on the hacker's card.
- The result: Your phone instantly loses signal (your card is deactivated). The hacker's phone gets a signal and, along with it, all your SMS messages with codes from the bank.
The warning signs
Unlike other viruses that stay hidden, here the effect is immediate:
- Total loss of signal: If you are in an area where you always have signal and suddenly "No Service" or "Emergency Calls Only" appears, it is a bad sign.
- Password reset notifications: If you receive emails saying your Instagram or banking app password was changed, but you did not request it.
How do you protect yourself from number theft?
Fortunately, you can defend yourself before it happens. Here are the essential measures:
- Stop using SMS for authentication: SMS is insecure. Use apps such as Google Authenticator or Microsoft Authenticator. They generate codes on your phone, which cannot be intercepted if someone steals your number.
- Set a PIN with your carrier: Call your phone company and ask for an additional PIN code or verbal password to be added to your account. Nobody can make changes (or swap the SIM) without that code.
- Be discreet online: Do not put your phone number publicly on social networks and do not answer quizzes that ask for your date of birth or your pet's name.
To better understand the technical details behind this type of attack, you can consult the explanations offered by security experts such as Microsoft on SIM Swapping threats.
Conclusion
Your phone number is more valuable than your wallet. If you suspiciously lose signal, do not wait. Call your carrier from another phone immediately. Speed of reaction can save your savings.
Do you want to secure your company accounts and implement authentication solutions that do not depend on SMS? Our team offers specialized consulting and IT services. Visit our contact page and let's talk.
This material is part of the Altanet educational series on digital safety. Want to know what other risks you are exposed to this year? See the Complete list of cyber threats in 2026.