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Description

The following analytic detects the assignment of the ApplicationImpersonation role in Office 365 to a user or application. It uses the Office 365 Management Activity API to monitor Azure Active Directory audit logs for role assignment events. This activity is significant because the ApplicationImpersonation role allows impersonation of any user, enabling access to and modification of their mailbox. If confirmed malicious, an attacker could gain unauthorized access to sensitive information, manipulate mailbox data, and perform actions as a legitimate user, posing a severe security risk to the organization.

  • Type: TTP

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

  • Last Updated: 2024-05-23
  • Author: Mauricio Velazco, Splunk
  • ID: 49cdce75-f814-4d56-a7a4-c64ec3a481f2

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1098 Account Manipulation Persistence, Privilege Escalation
T1098.002 Additional Email Delegate Permissions Persistence, Privilege Escalation
Kill Chain Phase
  • Installation
  • Exploitation
NIST
  • DE.CM
CIS20
  • CIS 10
CVE 


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`o365_management_activity` Workload=Exchange Operation="New-ManagementRoleAssignment"  Role=ApplicationImpersonation 
|  rename User as target_user 
| stats  max(_time) as lastTime by Operation, user, object, ObjectId, Role, target_user 
| `security_content_ctime(lastTime)` 
| `o365_applicationimpersonation_role_assigned_filter`

Macros

The SPL above uses the following Macros:

:information_source: o365_applicationimpersonation_role_assigned_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
  • Role
  • user
  • User
  • object
  • ObjectId

How To Implement

You must install the Splunk Microsoft Office 365 Add-on and ingest Office 365 management activity events.

Known False Positives

While infrequent, the ApplicationImpersonation role may be granted for leigimate reasons, filter as needed.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
56.0 80 70 $user$ granted the ApplicationImpersonation role to $target_user$

: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: 2