Multi-factor authentication (MFA) is a security procedure that requires users to log in with at least two different factors. In addition to a password, additional proof is required, e.g. a code on the smartphone.
The MFA combines different types of evidence:
Even if a password is stolen, an unauthorized person cannot log in without the second factor. MFA is therefore one of the most effective measures against unauthorized access.
Practical example from everyday work
Imagine an employee logs into her email inbox in the morning.
She enters her password as usual (knowledge). She then receives a request on her smartphone (possession), which she has to confirm with a click.
One day, her password is intercepted by a phishing email. A stranger then tries to log into her email account.
Although the password is correct, the login fails – because the attacker is unable to carry out the second confirmation on the smartphone.
Instead, the employee receives an unexpected login request on her cell phone and immediately realizes that something is wrong. She reports the incident to IT and changes her password.
Note: Unauthorized access was successfully prevented by MFA.
