Sigma Rule Library

Multi Factor Authentication Disabled For User Account

Detects changes to the "StrongAuthenticationRequirement" value, where the state is set to "0" or "Disabled". Threat actors were seen disabling multi factor authentication for users in order to maintain or achieve access to the account. Also see in SIM Swap attacks.

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Detection logic

selection

LoggedByService: Core Directory
Category: UserManagement
OperationName: Update user
TargetResources.ModifiedProperties.DisplayName: StrongAuthenticationRequirement
TargetResources.ModifiedProperties.NewValue|contains: State":0

Condition

selection

Raw YAML

title: Multi Factor Authentication Disabled For User Account
id: b18454c8-0be3-41f7-86bc-9c614611b839
status: test
description: |
    Detects changes to the "StrongAuthenticationRequirement" value, where the state is set to "0" or "Disabled".
    Threat actors were seen disabling multi factor authentication for users in order to maintain or achieve access to the account. Also see in SIM Swap attacks.
references:
    - https://www.sans.org/blog/defending-against-scattered-spider-and-the-com-with-cybercrime-intelligence/
author: Harjot Singh (@cyb3rjy0t)
date: 2024-08-21
tags:
    - attack.credential-access
    - attack.persistence
logsource:
    product: azure
    service: auditlogs
    definition: 'Requirements: The TargetResources array needs to be mapped accurately in order for this rule to work'
detection:
    selection:
        LoggedByService: 'Core Directory'
        Category: 'UserManagement'
        OperationName: 'Update user'
        TargetResources.ModifiedProperties.DisplayName: 'StrongAuthenticationRequirement'
        TargetResources.ModifiedProperties.NewValue|contains: "State\":0"
    condition: selection
falsepositives:
    - Legitimate authorized activity.
level: medium

False positives

  • Legitimate authorized activity.

References