What Is SMS 2FA? Bulk SMS Authentication Explained

When using Two-Factor Authentication (2FA) or Multi-Factor Authentication (MFA), SMS 2FA is a method of authentication that is frequently used in addition to the usual password. SMS two-factor authentication (SMS 2FA) entails texting the user a brief one-time password (OTP). In order to verify their identity and get access to their account, the user must input the one-time password into the log-in form.

In contrast to many other authentication techniques that demand a steady Internet connection, SMS-Based Two-Factor Authentication does not require your phone to be online.

How Does SMS Authentication Work?

SMS authentication is simple, which may be the reason it is still so common despite the availability of so many more secure authentication techniques.

SMS authentication functions generally in the way that follows:

1. User types in a password

2. The user gets an SMS containing a one-time password.

3. The user fills up the login form with their password.

4. User is granted entry

Most MFA/2FA service providers accept SMS authentication. For instance, Msgclub offers Bulk SMS Authentication in the form of an SMS Passcode, which is a text message one-time password authentication technique. The Two-Factor Authentication (2FA) procedure using Msgclub’s SMS Passcode is shown in the following illustration.

1. The user begins the login procedure.

2. The user logs in and enters their password.

3. The user decides to use SMS Passcode authentication.

4. The user fills out the log-in form with the SMS Passcode.

5. The Msgclub API verifies the code’s accuracy.

6. If the code is accurate, the user is allowed entry. In that case, Msgclub rejects the user.

Pros and Cons of SMS Authentication

Like other authentication techniques, SMS authentication has advantages and disadvantages of its own.

Pros of SMS 2FA:

  • works offline– phone not required to be online.
  • The low learning curve for users -SMS authentication is commonplace and simple.
  • Any phone that accepts SIM cards will work– There is no need for pricey smartphones.
  • No additional hardware or software is necessary– thus users do not need to install or purchase anything.
  • Mobile operating systems are not needed to be maintained up to date– Authenticator apps may not function on older operating systems, however, SMS authentication is unaffected by this and can be used on even the oldest phones.

Cons of SMS 2FA:

Costly – Each SMS message has a separate fee.

One-time passwords last for a very long time– For example, SMS OTPs expire after a few minutes, giving hackers time to launch a cyberattack.

SIM cards are simple to remove from one phone and install in another– it takes an attacker just a few seconds to do so from an unprotected phone.

Shoulder surfing issue – SMS notifications with visible passcodes can also leak through the phone’s lock screen, giving the code to an unauthorized person.

Depending on the device – You lose access to your account if you lose your phone or SIM card.

SMS 2FA Replacements

Given the numerous drawbacks of SMS 2FA, you might wish to think about a different method of MFA authentication. The three most well-liked options are:

Passcodes for TOTP

The most widely used substitute for SMS 2FA is TOTP Passcodes, or Mobile Passcodes as we prefer to refer to them. The Time-Based One-Time Password (TOTP) algorithm is used by TOTPs.

You input a one-time password during TOTP 2FA that was generated by a smartphone app that is loaded on your device. A crucial feature is that a new one-time password is produced every 30 seconds, giving potential attackers little time to launch a cyberattack.

Mobile Push

Mobile Pushes are requests for authentication that appear as phone alerts on your screen. You might need to launch the authenticator app before receiving the push, depending on the app.

You can review the login attempt’s details (location, time, username, and email address) after opening the push request and accept or reject the attempt.

One of the safest methods of authentication is a mobile push. Unlike TOTP and SMS Authentication, which both need the user to manually enter information, this method is more affordable. This makes Mobile Push immune to a variety of threats, including keylogging. Additionally, Mobile Push is a recognized type of OOBA (Out-of-Band Authentication).

Keys for WebAuthn/U2F security

The most secure available 2FA solution is WebAuthn/U2F Security Keys. There aren’t many drawbacks to security keys, but one of them is their price. Even so, these keys are particularly safe if you can afford them.

WebAuthn/U2F Security Keys have been found to be extremely effective against Man-in-the-Middle (MITM) attacks and are difficult to compromise. 

YubiKey Bio, one of the newest Security Key variations, supports biometric authentication. These biometric keys combine two reliable forms of identification—what you have and who you are—to provide the highest level of user security.

Msgclub Supports SMS 2FA (And More!)

Msgclub is a complete Multi-Factor Authentication (MFA) solution that uses SMS Authentication among other authentication techniques to secure your cloud applications, VPNs, and remote desktops.

You can try Msgclub for your staff for free by doing the following:

Start a Free Msgclub Trial

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