Query: actor TTPs: Multi-Factor Authentication Request Generation
Matching passage: T1621 Multi-Factor Authentication Request Generation. Tactics: credential access. Description: 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](https://attack.mitre.org/techniques/T1078) 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).(Citation: Obsidian SSPR Abuse 2023) 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.”(Citation: Russian 2FA Push Annoyance - Cimpanu)(Citation: MFA Fatigue Attacks - PortSwigger)(Citation: Suspected Russian Activity Targeting Government and Business Entities Around the Globe)
Near-miss passage: T1558.003 Kerberoasting. Tactics: credential access. Description: Adversaries may abuse a valid Kerberos ticket-granting ticket (TGT) or sniff network traffic to obtain a ticket-granting service (TGS) ticket that may be vulnerable to [Brute Force](https://attack.mitre.org/techniques/T1110).(Citation: Empire InvokeKerberoast Oct 2016)(Citation: AdSecurity Cracking Kerberos Dec 2015) Service principal names (SPNs) are used to uniquely identify each instance of a Windows service. To enable authentication, Kerberos requires that SPNs be associated with at least one service logon account (an account specifically tasked with running a service(Citation: Microsoft Detecting Kerberoasting Feb 2018)).(Citation: Microsoft SPN)(Citation: Microsoft SetSPN)(Citation: SANS Attacking Kerberos Nov 2014)(Citation: Harmj0y Kerberoast Nov 2016) Adversaries possessing a valid Kerberos ticket-granting ticket (TGT) may request one or more Kerberos ticket-granting service (TGS) service tickets for any SPN from a domain controller (DC).(Citation: Empire InvokeKerberoast Oct 2016)(Citation: AdSecurity Cracking Kerberos Dec 2015) Portions of these tickets may be encrypted with the RC4 algorithm, meaning the Kerberos 5 TGS-REP etype 23 hash of the service account associated with the SPN is used as the private key and is thus vulnerable to offline [Brute Force](https://attack.mitre.org/techniques/T1110) attacks that may expose plaintext credentials.(Citation: AdSecurity Cracking Kerberos Dec 2015)(Citation: Empire InvokeKerberoast Oct 2016) (Citation: Harmj0y Kerberoast Nov 2016) This same behavior could be executed using service tickets captured from network traffic.(Citation: AdSecurity Cracking Kerberos Dec 2015) Cracked hashes may enable [Persistence](https://attack.mitre.org/tactics/TA0003), [Privilege Escalation](https://attack.mitre.org/tactics/TA0004), and [Lateral Movement](https://attack.mitre.org/tactics/TA0008) via access to [Valid Accounts](https://attack.mitre.org/techniques/T1078).(Citation: SANS Attacking Kerberos Nov 2014)