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Description

The following analytic identifies when the 'full_access_as_app' permission, marked by the GUID 'dc890d15-9560-4a4c-9b7f-a736ec74ec40', is assigned to an application within Office 365 Exchange Online, identified by ResourceAppId '00000002-0000-0ff1-ce00-000000000000'. This permission grants broad control over Office 365 operations, including full access to all mailboxes and the capability to send emails as any user. The query utilizes the azure_monitor_aad data source, focusing on AuditLogs with the operation name 'Update application'. This monitoring is crucial for early detection of potential unauthorized access or data exfiltration, as the 'full_access_as_app' permission could lead to significant security incidents if exploited.

  • Type: TTP

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

  • Last Updated: 2024-01-29
  • Author: Mauricio Velazco, Splunk
  • ID: ae286126-f2ad-421c-b240-4ea83bd1c43a

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1098.002 Additional Email Delegate Permissions Persistence, Privilege Escalation
T1098.003 Additional Cloud Roles Persistence, Privilege Escalation
Kill Chain Phase
  • Installation
  • Exploitation
NIST
  • DE.CM
CIS20
  • CIS 10
CVE 


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`azure_monitor_aad` category=AuditLogs operationName="Update application"  
| eval newvalue = mvindex('properties.targetResources{}.modifiedProperties{}.newValue',0) 
| spath input=newvalue  
| search "{}.ResourceAppId"="00000002-0000-0ff1-ce00-000000000000"  "{}.RequiredAppPermissions{}.EntitlementId"="dc890d15-9560-4a4c-9b7f-a736ec74ec40" 
| eval Permissions = '{}.RequiredAppPermissions{}.EntitlementId' 
| stats count earliest(_time) as firstTime latest(_time) as lastTime values(Permissions) by user, object, user_agent, operationName 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `azure_ad_fullaccessasapp_permission_assigned_filter`

Macros

The SPL above uses the following Macros:

:information_source: azure_ad_fullaccessasapp_permission_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

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 through an EventHub. This analytic was written to be used with the azure:monitor:aad sourcetype leveraging the AuditLogs log category.

Known False Positives

The full_access_as_app API permission may be assigned to legitimate applications. Filter as needed.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
48.0 80 60 User $user$ assigned the full_access_as_app permission to the app registration $object$

: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: 1