Use of Legacy Authentication Protocols — Sigma Rule

Rule metadata and linked tags

Author: Yochana Henderson, '@Yochana-H'. Source status: test; severity: high. Source dates: 2022-06-17 / not supplied.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: cc6acbb1bec5df7c60bdbe7a5b13df11f7b231b972c0fcadf2a0e5f9fef038ff

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: Use of Legacy Authentication Protocols
id: 60f6535a-760f-42a9-be3f-c9a0a025906e
status: test
description: Alert on when legacy authentication has been used on an account
references:
    - https://learn.microsoft.com/en-gb/entra/architecture/security-operations-privileged-accounts
author: Yochana Henderson, '@Yochana-H'
date: 2022-06-17
tags:
    - attack.privilege-escalation
    - attack.persistence
    - attack.initial-access
    - attack.credential-access
    - attack.stealth
    - attack.t1078.004
    - attack.t1110
logsource:
    product: azure
    service: signinlogs
detection:
    selection:
        ActivityDetails: Sign-ins
        ClientApp:
            - Other client
            - IMAP
            - POP3
            - MAPI
            - SMTP
            - Exchange ActiveSync
            - Exchange Web Services
        Username: 'UPN'
    condition: selection
falsepositives:
    - User has been put in acception group so they can use legacy authentication
level: high

Original YAML and metadata in JSON

False positives

• User has been put in acception group so they can use legacy authentication

Source references

• https://learn.microsoft.com/en-gb/entra/architecture/security-operations-privileged-accounts