Increased Failed Authentications Of Any Type — Sigma Rule

Rule metadata and linked tags

Author: Mark Morowczynski '@markmorow', MikeDuddington, '@dudders1'. Source status: test; severity: medium. Source dates: 2022-08-11 / not supplied.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: f6a43e550abf054fe7a8e441ce7c2451e97b0e59a81d49fc1f71bedd13abe257

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: Increased Failed Authentications Of Any Type
id: e1d02b53-c03c-4948-b11d-4d00cca49d03
status: test
description: Detects when sign-ins increased by 10% or greater.
references:
    - https://learn.microsoft.com/en-us/entra/architecture/security-operations-user-accounts#monitoring-for-failed-unusual-sign-ins
author: Mark Morowczynski '@markmorow', MikeDuddington, '@dudders1'
date: 2022-08-11
tags:
    - attack.privilege-escalation
    - attack.persistence
    - attack.initial-access
    - attack.stealth
    - attack.t1078
logsource:
    product: azure
    service: signinlogs
detection:
    selection:
        Status: failure
        Count: "<10%"
    condition: selection
falsepositives:
    - Unlikely
level: medium

Original YAML and metadata in JSON

False positives

• Unlikely

Source references

• https://learn.microsoft.com/en-us/entra/architecture/security-operations-user-accounts#monitoring-for-failed-unusual-sign-ins