Detection rules › Sigma

Multi Factor Authentication Disabled For User Account

Status
test
Severity
medium
Log source
product azure, service auditlogs
Author
Harjot Singh (@cyb3rjy0t)
Source
github.com/SigmaHQ/sigma

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.

Known false positives

  • Legitimate authorized activity.

MITRE ATT&CK coverage

TacticTechniques
PersistenceNo specific technique
Credential AccessNo specific technique

Telemetry coverage

PlatformRecord / event type
AzureUpdate user

Rules detecting the same action

These rules filter on the same operation.

Rule body

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

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

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

Indicators

These rows show field, operator, and value matches.