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Description

The following analytic identifies an attempt to disable multi-factor authentication for an Azure AD user. An adversary who has obtained access to an Azure AD tenant may disable multi-factor authentication as a way to plant a backdoor and maintain persistence using a valid account. This way the attackers can keep persistance in the environment without adding new users.

  • Type: TTP
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud

  • Last Updated: 2022-08-10
  • Author: Mauricio Velazco, Splunk
  • ID: 482dd42a-acfa-486b-a0bb-d6fcda27318e

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1556 Modify Authentication Process Credential Access, Defense Evasion, Persistence
Kill Chain Phase
  • Installation
  • Actions on Objectives
NIST
  • DE.CM
CIS20
  • CIS 3
  • CIS 5
  • CIS 16
CVE
1
2
3
4
5
6
7
`azuread` body.category=AuditLogs body.operationName="Disable Strong Authentication" 
| rename body.properties.* as * 
| rename targetResources{}.userPrincipalName as userPrincipalName 
| rename targetResources{}.type as type 
| rename initiatedBy.user.userPrincipalName as initiatedBy 
| stats values(userPrincipalName) by _time, type, body.operationName, initiatedBy, result 
| `azure_ad_multi_factor_authentication_disabled_filter`

Macros

The SPL above uses the following Macros:

:information_source: azure_ad_multi-factor_authentication_disabled_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required fields

List of fields required to use this analytic.

  • _time
  • body.properties.targetResources{}.userPrincipalName
  • body.properties.targetResources{}.type
  • body.properties.initiatedBy.user.userPrincipalName
  • body.properties.result

How To Implement

You must install the latest version of Splunk Add-on for Microsoft Cloud Services from Splunkbase(https://splunkbase.splunk.com/app/3110/#/details). You must be ingesting Azure Active Directory events into your Splunk environment. Specifically, this analytic leverages the AuditLogs log category.

Known False Positives

Legitimate use case may require for users to disable MFA. Filter as needed.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
45.0 50 90 MFA disabled for User $userPrincipalName$ initiated by $initiatedBy$

:information_source: The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

Reference

Test Dataset

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

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