Passwords alone are no longer sufficient to protect users’ online accounts as cyberattacks become more frequent and advanced, hence, multi-factor authentication (MFA) is necessary to reduce the risk of unauthorised access to online accounts.
There are different types of MFA that use what the user has and who the user is. SMS-based Authentication, Biometrics Authentication, and Application-based Authentication are the most common types.
When a user turns on SMS-based authentication, they register a mobile number that is linked to their account. Most SMS-based OTPs are only good for a certain amount of time, usually 3 minutes, after which they can’t be used again.
When a user intends to log in to their account, the system produces an OTP and sends it to the registered phone number via SMS. The system then checks the OTP, and if they match, it lets the person into their account.
When a user turns on biometric authentication, they will have to enrol their biometric data into the system by capturing and storing their unique physical or behavioural traits in a digital format. This information can come from things like fingerprint scans, facial recognition, iris recognition, voice recognition, and more.
Besides, when a user attempts to log in to their account, their biometric data is used to verify the user’s identity by comparing the data to a list of existing users whose biometric data has been registered in the system. The user is granted access if the biometric data matches.
Similarly, when a user enables 2FA with an authenticator app on their account, they will typically be asked to scan a QR code or enter a secret key provided by the service into their authenticator app.
Once the secret key is entered, the authenticator app generates a unique OTP using an algorithm such as Time-based One-Time Password (TOTP) or HMAC-based One-Time Password (HOTP) that is valid for a specific time window, typically 30 seconds, before changing. To generate the OTP, the algorithm considers the secret key known only to the user and the app, as well as the current time.
After their regular password has been validated, the user will be prompted to enter the OTP generated by their authenticator app when attempting to log in to their account. The service will then compare the user’s input to that generated by the authenticator app. If the OTPs match, the user is granted account access.
Likewise, SMS-based 2FA works by texting an OTP to a user’s mobile phone. To complete the authentication process, the user must enter this OTP into the online service. While SMS-based 2FA provides an additional authentication method, it is not as secure as authenticator apps or biometrics because SMS can be compromised:
- SIM Swapping: Threat actors can use this technique to acquire phone numbers via data leaks, public records, or social engineering, then bribe or trick a service provider employee into porting the number to a duplicate SIM card under their control. This gives them the ability to intercept users’ SMS verification OTPs and gain unauthorised access to associated online accounts.
- SMS Phishing: Using SMS Phishing (Smishing), threat actors can intercept users’ SMS messages and steal verification OTP to gain access to their various online accounts.
Thus, authenticator apps and biometrics offer a higher level of security compared to other authentication methods like SMS-based 2FA. Users are advised to practice good cyber hygiene by using a strong password and selecting the most secure 2FA method to protect their online accounts.
