Multifactor Authentication Denied — Sigma Rule

Rule metadata and linked tags

Author: AlertIQ. Source status: test; severity: medium. Source dates: 2022-03-24 / not supplied.

{
  "product": "azure",
  "service": "signinlogs"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: ced77e7d3a0c4e1756c5f29bd6b860eb525dce951c014971e09e9fbf72203002

Detection logic

Original source YAML. Source-tag agreement is not proof of complete semantic coverage. This rule has not been compiled for a SIEM backend or validated against live telemetry here.

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

Original YAML and metadata in JSON

False positives

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

Source references

• https://www.microsoft.com/security/blog/2022/03/22/dev-0537-criminal-actor-targeting-organizations-for-data-exfiltration-and-destruction/