Detection rules › Sigma

Multifactor Authentication Denied

Status
test
Severity
medium
Log source
product azure, service signinlogs
Author
AlertIQ
Source
github.com/SigmaHQ/sigma

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

MITRE ATT&CK coverage

Rule body 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

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    AuthenticationRequirement: 'multiFactorAuthentication'
    Status|contains: 'MFA Denied'

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
AuthenticationRequirementeq
  • multiFactorAuthentication
Statusmatch
  • MFA Denied