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Description

The following analytic detects the addition of an application role assignment grant to a user in Office 365. It leverages data from the o365_management_activity dataset, specifically monitoring the "Add app role assignment grant to user" operation. This activity is significant as it can indicate unauthorized privilege escalation or the assignment of sensitive roles to users. If confirmed malicious, this could allow an attacker to gain elevated permissions, potentially leading to unauthorized access to critical resources and data within the Office 365 environment.

  • Type: TTP

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

  • Last Updated: 2024-05-19
  • Author: Rod Soto, Splunk
  • ID: b2c81cc6-6040-11eb-ae93-0242ac130002

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1136.003 Cloud Account Persistence
T1136 Create Account Persistence
Kill Chain Phase
  • Installation
NIST
  • DE.CM
CIS20
  • CIS 10
CVE 


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`o365_management_activity` Workload=AzureActiveDirectory Operation="Add app role assignment grant to user." 
| stats count min(_time) as firstTime max(_time) as lastTime values(Actor{}.ID) as Actor.ID values(Actor{}.Type) as Actor.Type values(ModifiedProperties{}.Name) as modified_properties_name by user dest ResultStatus Operation 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `o365_add_app_role_assignment_grant_user_filter`

Macros

The SPL above uses the following Macros:

:information_source: o365_add_app_role_assignment_grant_user_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
  • Workload
  • Operation
  • Actor{}.ID
  • Actor{}.Type
  • UserId
  • dest
  • ResultStatus

How To Implement

You must install splunk Microsoft Office 365 add-on. This search works with o365:management:activity

Known False Positives

The creation of a new Federation is not necessarily malicious, however this events need to be followed closely, as it may indicate federated credential abuse or backdoor via federated identities at a different cloud provider.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
18.0 30 60 User $user$ has created a new federation setting $modified_properties_name$ on $dest$

: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

source | version: 3