T1621: Multi-Factor Authentication Request Generation
Adversaries may attempt to bypass multi-factor authentication (MFA) mechanisms and gain access to accounts by generating MFA requests sent to users.
Adversaries in possession of credentials to Valid Accounts may be unable to complete the login process if they lack access to the 2FA or MFA mechanisms required as an additional credential and security control. To circumvent this, adversaries may abuse the automatic generation of push notifications to MFA services such as Duo Push, Microsoft Authenticator, Okta, or similar services to have the user grant access to their account. If adversaries lack credentials to victim accounts, they may also abuse automatic push notification generation when this option is configured for self-service password reset (SSPR).
In some cases, adversaries may continuously repeat login attempts in order to bombard users with MFA push notifications, SMS messages, and phone calls, potentially resulting in the user finally accepting the authentication request in response to “MFA fatigue.”
How it's found
Detection Strategy for Multi-Factor Authentication Request Generation (T1621): Monitor for excessive or anomalous MFA push notifications or token requests, especially when login attempts originate from unusual IPs or geolocations and do not correspond to legitimate user-initiated sessions. Detect abnormal MFA activity within cloud service provider logs, such as repeated generation of MFA challenges for the same user session or mismatched MFA device and login origin. Detect repeated failed login events followed by MFA challenges triggered in rapid succession, especially if originating from service accounts or anomalous IP addresses. Monitor PAM and syslog entries for unusual frequency of login attempts that trigger MFA prompts, particularly when MFA challenges do not match expected user behavior. Detect anomalous OAuth or SSO logins that repeatedly generate MFA challenges, particularly where MFA approvals are denied or timed out by the user. Detect user account logon attempts that trigger multiple MFA challenges through enterprise identity integrations, especially if MFA push requests are generated without successful interactive login.
Standards mapping
Where this fits in a TurboPentest engagement
This weakness is not covered by the automated black-box pentest. IntegSec pentesters cover it in a manual engagement.
Frequently asked questions
What is T1621 Multi-Factor Authentication Request Generation?
Adversaries may attempt to bypass multi-factor authentication (MFA) mechanisms and gain access to accounts by generating MFA requests sent to users. Adversaries in possession of credentials to Valid Accounts may be unable to complete the login process if they lack access to the 2FA or MFA mechanisms required as an additional credential and security control. To circumvent this, adversaries may abuse the automatic generation of push notifications to MFA services such as Duo Push, Microsoft Authenticator, Okta, or similar services to have the user grant access to their account. If adversaries lack credentials to victim accounts, they may also abuse automatic push notification generation when this option is configured for self-service password reset (SSPR). In some cases, adversaries may continuously repeat login attempts in order to bombard users with MFA push notifications, SMS messages, and phone calls, potentially resulting in the user finally accepting the authentication request in response to “MFA fatigue.”
Which tactics does T1621 belong to?
T1621 maps to the Credential Access tactic.
Does TurboPentest test for Multi-Factor Authentication Request Generation?
This weakness is not covered by the automated black-box pentest. IntegSec pentesters cover it in a manual engagement.
Related MITRE ATT&CK techniques
About this reference
These security references are maintained by IntegSec, an offensive-security firm whose team holds CISSP, OSCP, and OSCE certifications and has run thousands of penetration tests. Content is kept current as tools, standards, and attack techniques evolve.
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