SIM swapping: What it is, and how to protect yourself

What is a SIM swap?

A SIM swap scam is a type of SIM fraud where a malicious actor impersonates a legitimate user and convinces a mobile service provider to transfer the user’s phone number onto a SIM card controlled by the attacker. By doing so, the criminal gets access to the victim’s phone calls and text messages, which may include sensitive data. Additionally, they can exploit SMS-based two-factor authentication (2FA) and restore passwords.

Thus, the consequences of a SIM swap can be severe. Fraudsters may gain access to sensitive accounts like banking, email, and social media, potentially stealing personal and financial information and using it for gain. Plus, when a SIM swap attack occurs, the legitimate owner of the phone number typically loses service because their number is no longer linked to their original SIM card, leaving them unable to make calls, send texts, or access accounts linked to their number.

However, not all SIM swaps are malicious. Legitimate SIM swaps can be a convenient procedure if you lose your phone, your SIM card gets damaged, or your new phone requires a different-size SIM card. Mobile service providers may process SIM swapping in a few simple steps, ensuring you keep your original phone number. Unfortunately, a hacker might exploit this process for malicious purposes.

How does SIM swapping work?

SIM swapping, a type of identity theft, may sound like something out of a spy movie, but it’s a real threat with serious consequences for individuals and organizations. The attack usually starts with the attacker gathering as much personal information about the target as possible. The attacker usually needs common details such as the victim’s name, address, date of birth, and phone number to impersonate them and manipulate the mobile carrier. Thanks to social media and public databases, this data is relatively easy to access. That birthday selfie with a cake might just be what the fraudsters are looking for.

Armed with enough personal information, the attacker calls the mobile carrier and demonstrates their best acting skills to impersonate the victim. They usually create a fake story about a lost or damaged SIM and use the gathered information to pass security checks. Believing they’re helping the customer, the carrier then deactivates the victim’s legitimate SIM card and transfers the phone number to a new SIM card controlled by the attacker. Once this transfer is complete, the criminal gains full control of the victim’s phone number, including access to all calls and SMS messages.

However, your phone number is more than a tool for calling and texting. Many online services rely on SMS-based 2FA for added security. With control of your phone number, the attacker can request password resets for various accounts and receive verification codes via SMS. And as soon as the attacker gets them, you’re doomed. They’ve got access to your online life. They can now control your email and social media and even drain your bank or cryptocurrency accounts.

What are the signs of a SIM swap?

As threatening as it may sound, you have ways to prevent SIM swapping fraud and protect your social media accounts containing personal info and the money in your bank or credit card accounts. But first, let’s discuss how to spot SIM swapping. While these signs can be subtle, staying alert and vigilant can help you detect and stop attackers in their tracks.

Sudden loss of service

A sudden loss of service is often the first clue that something is wrong. If your phone unexpectedly loses signal and shows a “No service” message or your calls won’t go through, don’t brush it off as a simple network hiccup — especially if it lasts for hours or even longer. While temporary network glitches happen, if they last for several hours or even days, it could mean your SIM card has been hacked. In this case, it’s a good idea to contact your mobile carrier right away to check if something suspicious is happening.

Unusual messages or notifications

If you begin receiving unexpected notifications, such as text messages and emails about a new SIM activation or password changes, it could be a warning sign that your SIM was swapped. Even more concerning is if you receive messages confirming changes to your online accounts — especially if you never requested them.

Inability to access online accounts

If you cannot log in to your online accounts, especially if you are sure the login credentials are correct, it could be a red flag signaling that criminals have already changed your passwords. Since attackers often use SIM swapping to bypass 2FA, they might have locked you out of your digital accounts.

Unusual phone call activity

If you notice outgoing calls on your phone that you didn’t make or start getting calls from unfamiliar numbers, it could mean that someone else is using your phone number. However, it’s not always a sign of a SIM swap — scammers may also be targeting you with spam or phishing calls. Either way, don’t ignore it. If anything seems off, it’s worth looking into to make sure everything’s secure.

Unfamiliar transactions

Attackers who gain control of your phone number through a SIM swap might use it to reset passwords and access your financial accounts. They may initiate unauthorized transfers and withdrawals or even make purchases. If you notice unusual activity in your bank accounts, such as transfers you didn’t authorize or other financial activity you don’t recognize, it’s time to take action.

Inability to receive 2FA codes

If you suddenly cannot receive 2FA codes, it might be another red flag that you’re a victim of SIM swapping. Since 2FA codes are often sent through SMS, the attacker can intercept them and gain access to your protected accounts.

Risks of SIM swap attacks

Now, let’s explore the risks that go hand in hand with SIM swap fraud. Knowing what’s at stake can help you protect yourself and keep fraudsters out. Here’s what you should watch out for:

• Identity theft. Identity theft is one of the main and most serious risks associated with SIM swap scams. Once an attacker takes control of your phone number, they open the gate to your online world, including your phone calls, texts, emails, social media accounts, bank accounts, and subscription services. They can impersonate you, take out loans or open credit cards, damage your credit history, or even commit fraud in your name.
• Financial loss. Another goal of SIM swap fraud is to gain unauthorized access to your financial accounts. As soon as an attacker takes over your phone number, they can use it for account recovery or to bypass 2FA, which can lead to unauthorized financial transactions and loss of funds.
• Invasion of privacy. A successful SIM swap allows the attacker to invade your privacy. They can read your texts, access your photos, and go through your contacts, all without your knowledge.
• Loss of reputation. Someone controlling your phone number can send messages or emails, post to social media, or even conduct fraud in your name, potentially harming your relationships, professional reputation, or online presence.
• Psychological impact. We can’t forget the psychological burden of being the victim of a SIM swap scam. Victims often feel violated, anxious, and unsafe in the digital world, which can take a toll on their peace of mind.

What to do in the case of SIM swapping

If you suspect that you’ve fallen victim to a SIM swap, you have to act quickly to minimize damage. Take these steps immediately:

1. 1.Contact your mobile carrier. It’s the first thing you should do. Inform the representative that you suspect a SIM swap has occurred. The carrier can verify if a new card has been issued and suspend it.
2. 2.Change all account passwords and enable app-based 2FA. Secure all your online accounts as soon as possible, including those for your email, online banking, and social media accounts. Doing so will help prevent the attacker from accessing your sensitive information. For accounts that offer app-based 2FA, enable this feature immediately.
3. 3.Contact your bank or credit card company. If you suspect your financial accounts may have been affected, contact your financial company immediately. It can monitor and freeze your account in case someone makes unauthorized payments.
4. 4.Scan your devices for malware. Attackers may try to install malicious software to steal more personal details. Use anti-malware software to perform a deep scan and avoid any threats.
5. 5.Contact your local law enforcement. You might not be the only person targeted, and reporting the cybercrime could help prevent others from falling into the same trap. Fraud report options vary depending on your country. Many have cybercrime units that handle such incidents. In the USA, you can report the incident to the Federal Trade Commission (FTC), while in the UK, you should contact Action Fraud.

How to protect yourself from SIM swapping

Now that you know the risks of SIM swapping, let’s explore a few smart strategies to protect your phone number against SIM swaps. While these steps might not stop SIM swaps directly, they offer important protection against all kinds of cyberattacks and help keep your digital assets safe overall:

• Enable additional security measures. If your mobile carrier offers additional security measures, set them up. Mobile carriers usually provide a unique personal identification number (PIN) or passcode that you have to provide before any changes can be made.
• Beware of phishing attempts. Always be cautious about social engineering techniques that scammers use to get information about you. Watch out for unsolicited requests for personal details, especially when it comes to Social Security numbers or banking credentials. Remember — real service providers will never ask for such information via email or text.
• Use authentication apps. Enable 2FA, and opt for the app-based version if it’s available. These apps generate codes on your device, which reduces the risk of the process being intercepted by cybercriminals during the authentication process.
• Use unique passwords for your accounts. One of the best ways to protect your personal information is to create strong and unique passwords for each account. Avoid using easily guessable passwords or reusing passwords across multiple sites. Make sure your password is a combination of uppercase letters, lowercase letters, numbers, and symbols.
• Limit the information that you share online. The more personal information you share online, the easier it becomes for hackers to impersonate you. Be mindful of what you post on social media and avoid sharing sensitive details like your address, phone number, or birthdate. So no more birthday selfies!