Why You Should Stop Using SMS-Based Two-Factor Authentication

Two-Factor Authentication (2FA) is an essential security measure that adds an extra layer of protection to your online accounts. However, not all 2FA methods are equally secure. Many users rely on SMS-based 2FA, where a one-time password (OTP) is sent via text message to verify logins. While this method is better than using only a password, it comes with serious security risks that make it an outdated and vulnerable authentication method.

In this article, we’ll explore why SMS-based 2FA is risky, the most common attacks targeting it, and safer alternatives to secure your accounts.

Why SMS-Based 2FA is Insecure

1. SIM Swapping Attacks

One of the biggest threats to SMS-based 2FA is SIM swapping, where attackers trick mobile carriers into transferring your phone number to a SIM card they control. Once they gain control, they can intercept your 2FA codes and gain access to your accounts, even if you have a strong password.

🔹 How it happens:

• The hacker collects personal details about you (name, date of birth, phone number, etc.).

• They contact your mobile carrier and pretend to be you, requesting a SIM card transfer.

• Once the carrier approves the request, the hacker receives your SMS messages, including 2FA codes.

• They use the stolen codes to log into your accounts and lock you out.

This attack has been used in major cybercrimes, including cryptocurrency thefts, bank fraud, and identity theft.

2. SMS Interception & Man-in-the-Middle Attacks

Hackers can intercept SMS messages in multiple ways:

• SS7 Exploits: The Signaling System No. 7 (SS7) protocol is outdated and vulnerable. Cybercriminals can exploit SS7 to redirect your text messages to their device without touching your SIM card.

• Public Wi-Fi Attacks: If you receive 2FA codes over an unencrypted Wi-Fi network, an attacker may use a Man-in-the-Middle (MITM) attack to intercept your messages.

• Malware & Keyloggers: If your phone is infected with malware, hackers can access your text messages and steal 2FA codes.

In all these cases, the attacker can bypass your SMS-based 2FA and gain unauthorized access to your accounts.

3. Phishing Attacks

Hackers often use phishing scams to trick users into revealing their SMS-based 2FA codes.

🔹 How it happens:

• You receive a fake email or SMS pretending to be from a trusted company (e.g., Google, Facebook, or your bank).

• The message claims there is a security issue and asks you to enter your login credentials and 2FA code on a fake website.

• Once you submit the code, the hacker instantly uses it to access your account.

Since SMS codes are valid only for a short time, phishing attacks often happen in real-time using automated tools.

4. Mobile Number Recycling & Data Leaks

Many mobile carriers recycle old phone numbers, which means if you stop using your number, it could be reassigned to a new person. If your old number was linked to accounts with SMS-based 2FA, someone else could receive your authentication codes.

Additionally, data breaches have exposed millions of phone numbers. Hackers use leaked numbers for targeted SIM swap scams, social engineering attacks, or phishing.

Better Alternatives to SMS-Based 2FA

Since SMS-based 2FA is vulnerable, it’s time to switch to stronger authentication methods. Here are the best alternatives:

1. Authentication Apps (TOTP – Time-Based One-Time Passwords)

Apps like Google Authenticator, Microsoft Authenticator, and Authy generate random, time-sensitive codes that refresh every 30 seconds. These codes are:
✔ Stored securely on your device
✔ Not dependent on mobile networks or carriers
✔ Not vulnerable to SIM-swapping or SMS interception

🔹 How to enable it:

• Go to your account settings and choose 2FA with an authentication app.

• Scan the provided QR code with the authenticator app.

• Use the generated 6-digit code to log in securely.

2. Hardware Security Keys (FIDO2 & U2F Keys)

A hardware security key (such as YubiKey, Google Titan, or Feitian) is a physical device that provides unbreakable security against phishing and remote attacks.

🔹 Why it’s the best security option:
✔ No codes to intercept – You simply tap the device when logging in.
✔ Phishing-proof – The key verifies the website before allowing login.
✔ Immune to SIM swapping – It doesn’t rely on phone numbers.

How to use it:

• Purchase a FIDO2-compliant security key.

• Register it in the security settings of your online accounts.

• Insert the key into your device (or use NFC) and tap it to authenticate.

✅ Best for: Bank accounts, cryptocurrency wallets, email accounts, and high-security logins.

3. Biometric Authentication

Many modern devices support biometric authentication, such as:

• Fingerprint scanners (Touch ID, Windows Hello, Android Biometrics)

• Facial recognition (Face ID)

🔹 Pros:
✔ Easy to use and secure
✔ Cannot be intercepted remotely
✔ Eliminates the need for SMS codes

🔹 Cons:
❌ Not all websites support biometric logins
❌ Can be bypassed with deepfake technology (in some cases)

4. Passkeys (Passwordless Authentication)

Passkeys are the future of secure authentication and are supported by Apple, Google, and Microsoft.

✔ No passwords or SMS codes
✔ Uses cryptographic keys stored on your device
✔ Cannot be stolen via phishing

You can enable passkeys in Google, iCloud, and Microsoft accounts for stronger security than SMS-based 2FA.

How to Disable SMS-Based 2FA and Upgrade to a Safer Method

🔹 Step 1: Go to your online account’s security settings.
🔹 Step 2: Disable SMS-based 2FA (if required, set up another method first).
🔹 Step 3: Enable Authenticator App, Security Key, or Passkey as your new authentication method.
🔹 Step 4: Test your login to ensure the new method works.