Sigma Rule Library

Multifactor Authentication Denied

User has indicated they haven't instigated the MFA prompt and could indicate an attacker has the password for the account.

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Detection logic

selection

AuthenticationRequirement: multiFactorAuthentication
Status|contains: MFA Denied

Condition

selection

Raw YAML

title: Multifactor Authentication Denied
id: e40f4962-b02b-4192-9bfe-245f7ece1f99
status: test
description: User has indicated they haven't instigated the MFA prompt and could indicate an attacker has the password for the account.
references:
    - https://www.microsoft.com/security/blog/2022/03/22/dev-0537-criminal-actor-targeting-organizations-for-data-exfiltration-and-destruction/
author: AlertIQ
date: 2022-03-24
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:
        AuthenticationRequirement: 'multiFactorAuthentication'
        Status|contains: 'MFA Denied'
    condition: selection
falsepositives:
    - Users actually login but miss-click into the Deny button when MFA prompt.
level: medium

False positives

  • Users actually login but miss-click into the Deny button when MFA prompt.

References

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