Sigma Rule Library

Multifactor Authentication Interrupted

Identifies user login with multifactor authentication failures, which might be an indication an attacker has the password for the account but can't pass the MFA challenge.

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Detection logic

selection_50074

ResultType: 50074
ResultDescription|contains: Strong Auth required

selection_500121

ResultType: 500121
ResultDescription|contains: Authentication failed during strong authentication request

Condition

1 of selection_*

Raw YAML

title: Multifactor Authentication Interrupted
id: 5496ff55-42ec-4369-81cb-00f417029e25
status: test
description: Identifies user login with multifactor authentication failures, which might be an indication an attacker has the password for the account but can't pass the MFA challenge.
references:
    - https://learn.microsoft.com/en-us/entra/architecture/security-operations-privileged-accounts
author: AlertIQ
date: 2021-10-10
modified: 2022-12-18
tags:
    - attack.privilege-escalation
    - attack.persistence
    - attack.initial-access
    - attack.credential-access
    - attack.stealth
    - attack.t1078.004
    - attack.t1110
    - attack.t1621
logsource:
    product: azure
    service: signinlogs
detection:
    selection_50074:
        ResultType: 50074
        ResultDescription|contains: 'Strong Auth required'
    selection_500121:
        ResultType: 500121
        ResultDescription|contains: 'Authentication failed during strong authentication request'
    condition: 1 of selection_*
falsepositives:
    - Unknown
level: medium

False positives

  • Unknown

References

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