Detection rules › Sigma

Device Registration or Join Without MFA

Status
test
Severity
medium
Log source
product azure, service signinlogs
Author
Michael Epping, '@mepples21'
Source
github.com/SigmaHQ/sigma

Monitor and alert for device registration or join events where MFA was not performed.

MITRE ATT&CK coverage

Rule body yaml

title: Device Registration or Join Without MFA
id: 5afa454e-030c-4ab4-9253-a90aa7fcc581
status: test
description: Monitor and alert for device registration or join events where MFA was not performed.
references:
    - https://learn.microsoft.com/en-us/entra/architecture/security-operations-devices#device-registrations-and-joins-outside-policy
author: Michael Epping, '@mepples21'
date: 2022-06-28
tags:
    - attack.privilege-escalation
    - attack.persistence
    - attack.initial-access
    - attack.stealth
    - attack.t1078.004
logsource:
    product: azure
    service: signinlogs
detection:
    selection:
        ResourceDisplayName: 'Device Registration Service'
        conditionalAccessStatus: 'success'
    filter_mfa:
        AuthenticationRequirement: 'multiFactorAuthentication'
    condition: selection and not filter_mfa
falsepositives:
    - Unknown
level: medium

Stages and Predicates

Stage 0: condition

selection and not filter_mfa

Stage 1: selection

selection:
    ResourceDisplayName: 'Device Registration Service'
    conditionalAccessStatus: 'success'

Stage 2: not filter_mfa

filter_mfa:
    AuthenticationRequirement: 'multiFactorAuthentication'

Exclusions

Top-level NOT(...) conjuncts: predicates this rule actively suppresses.

FieldKindExcluded values
AuthenticationRequirementeqmultiFactorAuthentication

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
ResourceDisplayNameeq
  • Device Registration Service
conditionalAccessStatuseq
  • success