SIM swapping, also called SIM jacking, is a cyberattack where criminals take over your phone number to intercept sensitive information like two-factor authentication (2FA) codes. This lets them access your online accounts, steal money, and even commit identity theft.

Key Points:

How It Works: Attackers gather personal details (e.g., phone number, ID) via phishing or social engineering, then trick mobile carriers into transferring your number to their SIM card.
Why It Happens: Weaknesses in carrier security make SMS-based 2FA vulnerable.
Risks: Financial fraud, account takeovers (banking, cryptocurrency, social media), and privacy breaches.
Prevention:
- Enable carrier security features like SIM locks and transfer PINs.
- Use authentication apps or hardware keys instead of SMS for 2FA.
- Protect your phone number with disposable SIM services like MobileSMS.io.

Quick Tip:

If your phone suddenly loses service or you notice unusual account activity, act fast. Contact your carrier, freeze accounts, and update passwords immediately. SIM swapping is growing rapidly, with the FBI reporting $49 million in losses in 2023 alone. Take steps now to secure your digital life.

How SIM Swapping Works

SIM swapping is a calculated scheme that preys on both human behavior and gaps in system security. It unfolds in a series of steps: first, gathering personal information, followed by manipulating mobile carriers to gain control of the victim’s phone number.

It all starts with attackers collecting sensitive details about their target. They use various methods, including phishing emails disguised as legitimate services, mining social media profiles, or even tricking individuals through fake job offers or account update requests. These tactics are designed to extract critical information like phone numbers, national IDs, and account credentials.

"SIM swapping fraud typically begins when the fraudster acquires sensitive information about the victim, such as their national ID, phone number, and card details. This information is often obtained through phishing websites that mimic legitimate services or via social engineering tactics." – Group-IB

Once the attackers have enough data, they contact the victim’s mobile carrier. Pretending to be the victim, they claim that their SIM card has been lost, stolen, or damaged and request a transfer of the phone number to a new SIM card. By exploiting customer service protocols, they convince representatives to approve the transfer. At this point, all calls, text messages, and authentication codes are redirected to the attacker’s device.

Next, let’s look at how weaknesses in carrier systems make this possible.

Mobile Carrier Vulnerabilities

The success of SIM swapping hinges on flaws in mobile carrier processes. Carriers face challenges in distinguishing actual customers from skilled fraudsters, especially during the porting process – a legitimate service that allows users to transfer their number between devices or carriers. Customer service representatives typically rely on knowledge-based authentication, asking for details like billing history or personal information. Unfortunately, if attackers already have this information, these checks fail.

The problem has escalated significantly. Between 2018 and 2020, the FBI recorded 320 SIM swap complaints, with victims losing around $12 million. By 2021, incidents soared to 1,611, with losses exceeding $68 million. Some attackers bypass social engineering altogether by bribing carrier employees to sidestep security protocols.

In response, carriers have introduced measures like requiring account PINs, sending email-based verification codes for changes, and training employees to spot fraudulent requests. However, the battle between improving security and evolving criminal tactics is far from over.

These vulnerabilities make SMS-based two-factor authentication (2FA) a prime target.

Why SMS-Based 2FA Is Targeted

SMS-based 2FA relies on the assumption that the phone number is secure. But when a SIM swap occurs, this assumption breaks down, as attackers gain control of the number – and with it, access to verification codes.

"SIM swap fraud occurs when scammers take advantage of a weakness in two-factor authentication and verification and use your phone number to access your accounts." – Dan Rafter, Freelance writer

This vulnerability becomes even more dangerous because people often use the same phone number across multiple accounts. Once attackers gain control, they can focus on high-value targets like banking apps, cryptocurrency wallets, social media accounts, and email platforms that rely on SMS for password resets or logins. Often, they start by compromising less-secure accounts and use them to gain access to more critical ones.

High-profile incidents highlight the risks. For example, in 2019, Jack Dorsey’s Twitter account was hacked through a SIM swap, proving that even those well-versed in tech are not immune when SMS-based authentication becomes the weak spot.

To address this issue, services like MobileSMS.io offer a creative solution: disposable, SIM-based phone numbers for verification. These temporary numbers protect your primary phone number from exposure while still allowing SMS-based authentication when necessary, adding an extra layer of security against SIM swapping attacks.

Risks of SIM Swapping Attacks

SIM swapping is a dangerous tactic that exploits weaknesses in carrier systems and SMS-based two-factor authentication (2FA). Once attackers gain control of your phone number, they can wreak havoc on your finances, privacy, and even your identity. Here’s a closer look at the risks this attack poses.

Financial Fraud and Account Takeovers

When attackers hijack your phone number, banking and investment accounts become prime targets. By bypassing SMS-based 2FA, they can quickly drain checking accounts, initiate wire transfers, and access investment portfolios. The financial damage can be devastating.

For instance, cryptocurrency wallets are especially vulnerable. Cryptocurrency transactions are irreversible, making recovery nearly impossible. In one case, a victim lost $25,000 in cryptocurrency as attackers moved the stolen funds through multiple wallets and exchanges to cover their tracks.

Real-life examples highlight the severity of these attacks. Justin Chan, a Bank of America customer, lost $38,000 after attackers used SIM swapping to bypass authentication and transfer funds. Similarly, digital currency investor Michael Terpin suffered a staggering $23.8 million loss in 2018, leading him to sue the attackers. Businesses aren’t spared either – corporate accounts tied to financial systems, payroll platforms, or customer payment systems are at risk. The September 2023 MGM Resorts attack, where the group Scattered Spider exploited helpdesk staff, underscores how SIM swapping can cripple entire organizations.

Identity Theft and Privacy Breaches

The damage doesn’t stop at financial theft. SIM swapping opens the door to identity theft, allowing attackers to reset passwords, hijack accounts, and access private data.

"After the SIM swap, attackers intercept messages to reset passwords and access accounts." – FBI

Social media account takeovers add to the chaos. In January 2024, attackers used SIM swapping to hijack the U.S. Securities and Exchange Commission’s Twitter account. They posted a fake announcement about Bitcoin Exchange-Traded Fund approvals, briefly inflating Bitcoin prices and damaging the SEC’s credibility. Even prominent figures aren’t safe – former Twitter CEO Jack Dorsey’s account was compromised in a similar attack in 2019.

Healthcare data is another vulnerable area. In one case, attackers stole 800 GB of sensitive data, including protected health information, from a healthcare company after a successful SIM swap. This type of breach exposes medical records, insurance details, and personal information, fueling long-term fraud. Victims often describe the emotional toll as overwhelming, with feelings of violation and helplessness as their digital lives unravel.

Statistics and Real Cases

The numbers paint a grim picture. According to the FBI’s 2023 Internet Crime Report, victims lost nearly $49 million to SIM swapping attacks in that year alone. The problem has grown dramatically – complaints surged from 320 cases with $12 million in losses (2018–2020) to 1,611 cases with $68 million in losses by 2021. By December 2024, the FBI had recorded 800 cases nationwide, with SIM swapping incidents rising almost 400% compared to the previous year.

"The crime cost victims more than $48 million dollars nationally last year, according to the FBI."

This isn’t just a U.S. issue. In the UK, CIFAS, the national fraud prevention service, reported a dramatic increase in SIM swap incidents – from under 300 in 2022 to nearly 3,000 in 2023, a tenfold jump in just one year.

"As one brazen threat actor told Coalition Incident Response (CIR), SIM swapping attacks have a 100% guaranteed success rate – so once a target is identified, it’s not a matter of if, but when they’ll be compromised."

Given the growing risks, it’s clear that stronger defenses are needed. Tools like MobileSMS.io offer a practical solution by providing disposable, SIM-based phone numbers for verification. This keeps your real number private, reducing the chances of being targeted while still allowing you to use SMS-based authentication securely. Awareness and proactive measures are key to staying ahead of these attacks.

How to Detect and Respond to SIM Swap Attacks

Taking quick action is crucial when dealing with SIM swap attacks. Here’s how to spot the warning signs and what steps to take if you suspect you’re a victim.

Warning Signs of SIM Swapping

One of the first red flags of a SIM swap attack is losing cellular service. If your phone suddenly shows no signal and you can’t make calls or send texts, it could mean that your phone number has been transferred to someone else’s device, rendering your SIM card useless.

Pay attention to notifications from your mobile carrier. If you receive an email or text saying your SIM card has been activated on a new device without your request, it’s a strong indicator of unauthorized activity.

Account access issues often follow. You might find yourself locked out of important accounts like email, banking, or social media. This happens because attackers often use SMS-based password resets to take control.

Unusual account alerts can also be a clue. Notifications about password resets, logins from unfamiliar locations, or changes to your accounts might appear before you lose phone service. These alerts can give you a critical chance to act quickly.

Another tactic attackers use is sending you suspicious communications. For instance, they might flood your phone with calls or texts, encouraging you to turn it off. This distraction helps them complete the SIM swap unnoticed.

A real-world example highlights the risks: in January 2022, an individual lost cellular service and access to accounts, resulting in the theft of $15,000 in cryptocurrency.

If you notice any of these signs, it’s essential to act immediately.

Immediate Response Steps

Start by contacting your mobile carrier to report the suspected SIM swap and regain control of your number. Use the following numbers for quick assistance:

Verizon: *611
AT&T: 1-800-331-0500
T-Mobile: 1-800-937-8997
US Cellular: 1-888-944-9400

Explain the situation and let them know your number has been transferred without authorization.

"As soon as you suspect something is wrong – act. The longer it takes to react, the potential for more impacting activity by the attacker is possible." – The Cyber Helpline

Next, contact your bank and credit card companies to alert them about the attack. Request a temporary freeze on your accounts to prevent unauthorized transactions. Review your recent activity and dispute any fraudulent charges immediately.

Update the passwords for your most critical accounts, such as email, banking, and any others tied to your phone number. Use a secure device to create strong, unique passwords, and temporarily disable SMS-based two-factor authentication. Once your phone service is restored, consider switching to an authentication app for added security.

Keep a detailed record of your actions, including contact times, steps taken, and any reference numbers. This information can be valuable for filing insurance claims, police reports, or following up with financial institutions.

Monitor your accounts regularly. Check bank statements, credit card activity, and online accounts for unusual behavior. Remove unfamiliar devices from your account security settings and enable alerts for login attempts or account changes.

Finally, report the attack to the appropriate authorities. File a report with your local police and submit a complaint to the FBI’s Internet Crime Complaint Center (IC3) online. If cryptocurrency theft is involved, notify any relevant exchange platforms as well.

While a SIM swap attack can be stressful, acting quickly and methodically can help you regain control and limit the damage. To reduce your chances of being targeted in the future, consider using services like MobileSMS.io, which provide disposable, non-VoIP phone numbers for account verification. This keeps your real number private and adds an extra layer of protection.

How to Prevent SIM Swapping

SIM swapping is a growing threat, but you can take proactive steps to protect your phone number and accounts. By combining carrier security features, privacy tools, and stronger authentication methods, you can significantly reduce your risk.

Carrier Security Features

Your mobile carrier offers tools to make SIM swapping much harder for scammers. These features add extra layers of verification, ensuring that unauthorized changes to your account are blocked.

Enable SIM Protection: Many carriers, like Verizon, allow you to lock your SIM card to prevent unauthorized changes. For instance, Verizon’s free SIM Protection feature blocks any requests for SIM changes unless you disable the lock yourself.

"At no cost to you, SIM Protection offers you the ability to lock lines on your account to prohibit changes to the SIM cards associated with those lines. No request to change your SIM will be processed until you unlock the SIM protection feature on the line." – Verizon

Set Up a Number Transfer PIN: This PIN is required when porting your number to a different provider. You can contact your carrier to enable this feature. Verizon users can dial #PORT to request their PIN.
Create a Strong Account Passcode: Add a passcode to your carrier account to prevent unauthorized access. Avoid using simple combinations like birthdates. Carriers like AT&T and T-Mobile allow you to set up passcodes or PINs through their apps or websites.
Activate a SIM PIN on Your Device: This adds an extra layer of security by requiring a PIN whenever your device restarts or the SIM is removed. On iPhones, you can enable this through Settings > Cellular > SIM PIN. For Android, go to Settings > Security > SIM card lock.

Additionally, AT&T users can enable a Wireless Account Lock through the myAT&T app to prevent unauthorized changes to their account or billing information.

Using Privacy-Focused Solutions Like MobileSMS.io

Keeping your personal number private can reduce your exposure to SIM swapping. One way to do this is by using disposable SIM numbers for online account verification.

MobileSMS.io offers real, non-VoIP SIM numbers for secure SMS verification. Unlike VoIP numbers that many platforms reject, these numbers work with services like Google, Telegram, and WhatsApp. Since 2018, MobileSMS.io has helped users protect their privacy with both short-term and long-term SIM options.

For instance, their All Services Premium Long-Term Number includes integrations with platforms like Slack and Discord, making it ideal for teams managing multiple accounts. By using a separate number for verification, you can shield your personal number from attackers, spam, and phishing attempts.

Better 2FA Methods Than SMS

While SMS-based two-factor authentication (2FA) is common, it’s also one of the easiest methods for attackers to exploit. Switching to more secure options can greatly enhance your account protection.

Authentication Apps: Apps like Google Authenticator, Microsoft Authenticator, or Authy generate time-sensitive codes that don’t rely on your phone number. These codes refresh every 30 seconds and work offline, making them much harder to intercept.
Hardware Security Keys: Devices like YubiKey offer an even higher level of security. These physical keys connect via USB or Bluetooth and require your physical presence to authenticate access.
Push Notifications: Some services let you approve logins through their app instead of using SMS codes. This method bypasses phone networks entirely, adding another layer of security.

For critical accounts – like email, banking, and cryptocurrency platforms – start by enabling app-based or hardware-based 2FA. Many services allow you to keep SMS as a backup option while using stronger methods as your primary defense.

Final Tips for Staying Secure

Beyond carrier features and 2FA upgrades, there are additional steps you can take:

Use a password manager to create and store complex, unique passwords for each account.
Be cautious of unsolicited messages or calls asking for personal information, as these could be phishing attempts.
Regularly monitor your accounts for any unusual activity.

The FBI received 1,611 SIM swapping complaints in 2021, with reported losses exceeding $68 million. These numbers highlight how critical it is to secure your accounts.

"Fraudsters may be able to take over your phone number with a SIM swap or port-out scam and then break into your online accounts. You can protect yourself by enabling security measures from your carrier and adding extra protections to your accounts." – Louis DeNicola, Freelance Personal Finance and Credit Writer

Conclusion

SIM swapping poses a serious risk to SMS-based two-factor authentication (2FA). Just consider this: in 2021 alone, the FBI reported 1,611 cases of SIM swapping, leading to losses exceeding $68 million. That’s a massive jump compared to the $12 million in losses recorded between 2018 and 2020.

These numbers highlight one thing – it’s time to take your account security seriously. Start by enabling SIM protection through your carrier, setting strong account passcodes, and using privacy-focused tools to safeguard your personal number. Want an extra layer of defense? Use disposable SIM numbers for online verifications to keep your primary number out of reach.

Another key step is moving away from SMS-based 2FA. While convenient, SMS simply can’t keep up with today’s threats. Instead, rely on options like authentication apps, hardware security keys, or push notifications. These methods offer a much stronger shield against attacks.

As cyber threats continue to evolve, staying ahead with strong, layered defenses is essential. Combine secure carrier protocols with alternative authentication methods to protect your financial accounts, personal data, and digital identity.

"SIM swapping can create many financial and social difficulties for those who fall victim to these malicious attacks." – Kaspersky

The time to act is now – take these steps to secure your digital life.

FAQs

How can I know if my phone number has been targeted in a SIM swap attack?

If you’ve fallen victim to a SIM swap attack, you’ll likely notice some immediate warning signs. Your phone service might suddenly stop working – no calls, texts, or mobile data. You could also get unexpected alerts from your carrier about changes to your SIM card or account. On top of that, you might see unusual activity on your online accounts, such as password reset requests or logins you didn’t authorize.

If any of this happens, take action right away. Contact your mobile provider to lock down your account and check your online accounts for any suspicious access. Time is critical in these situations.

What should I do right away if I think I’ve been targeted by SIM swapping?

If you think you’ve fallen victim to SIM swapping, it’s crucial to act fast to limit the damage. Start by reaching out to your mobile provider right away. Let them know about the issue, report the unauthorized activity, and ask them to block your number to stop further misuse.

After that, update the passwords for any accounts tied to your phone number. Focus on your most sensitive accounts first – financial, email, and social media platforms. Whenever possible, switch to app-based two-factor authentication (2FA) instead of relying on SMS for added protection. Keep a close watch on your accounts for any unusual activity, and if you spot something suspicious – like unauthorized transactions – report it to the relevant institutions immediately. You might also want to place a fraud alert on your credit report to add an extra layer of protection against identity theft.

Acting quickly on these steps can help protect your personal information and reduce the fallout from a SIM swapping attack.

Why is SMS-based two-factor authentication (2FA) considered less secure?

Why SMS-Based Two-Factor Authentication Isn’t the Best Choice

SMS-based two-factor authentication (2FA) might seem like a convenient way to add an extra layer of security to your accounts, but it comes with some serious risks. One of the biggest vulnerabilities is SIM swapping. This is when a hacker tricks your mobile carrier into transferring your phone number to their SIM card. Once they have control of your number, they can intercept your SMS messages, including those critical 2FA codes. If they also have your password, they could gain full access to your accounts.

Another issue with SMS 2FA is that text messages aren’t encrypted. This makes them easier to intercept while they’re being transmitted, leaving your sensitive information exposed. While SMS-based 2FA is certainly better than relying on a password alone, it’s not the best choice for situations where security is a top priority. For stronger protection, experts recommend using authenticator apps or hardware tokens, which are far more secure alternatives.

What Is SIM Swapping in 2FA?