Risky Bulletin Newsletter
October 28, 2022
Risky Biz News: Microsoft rolls out number matching to counter MFA push notification spam attacks
Presented by
News Editor
The new "number matching" feature works to protect accounts by showing a number inside the push notification message received by account owners. Even if the user clicks "yes/approve" by accident, the attacker won't be able to log in without entering this number as well, which most attackers would not be able to do.
Microsoft announced this feature earlier this year—after Lapsus$ compromised its network—but a similar number matching feature has also been available in other secure authentication providers like Cisco Duo, Okta, and others.
However, it must be mentioned that this technique is not foolproof, and attackers who contact employees posing as IT staff have been known to extract these numbers from employees in some attacks. But if you're forcing employees into MFA that rely on push notifications, it's better to have numbers matching enabled than not. Either way, if FIDO-based MFA is an option, better use that, as that form of cryptographic device-based authentication is not vulnerable to MFA fatigue attacks.