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Description

The following analytic identifies instances where a user in the Office 365 environment grants consent to an application requesting file permissions for OneDrive or SharePoint. It leverages O365 audit logs, focusing on OAuth application consent events. This activity is significant because granting such permissions can allow applications to access, modify, or delete files, posing a risk if the application is malicious or overly permissive. If confirmed malicious, this could lead to data breaches, data loss, or unauthorized data manipulation, necessitating immediate investigation to validate the application's legitimacy and assess potential risks.

  • Type: TTP

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

  • Last Updated: 2024-05-27
  • Author: Mauricio Velazco, Splunk
  • ID: 6c382336-22b8-4023-9b80-1689e799f21f

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1528 Steal Application Access Token Credential Access
Kill Chain Phase
  • Exploitation
NIST
  • DE.CM
CIS20
  • CIS 10
CVE 


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`o365_management_activity` Workload=AzureActiveDirectory Operation="Consent to application." ResultStatus=Success 
| eval admin_consent =mvindex('ModifiedProperties{}.NewValue', 0) 
| search admin_consent=False 
| eval permissions =mvindex('ModifiedProperties{}.NewValue', 4) 
| rex field=permissions "Scope: (?<Scope>[^,]+)" 
| makemv delim=" " Scope 
| search Scope IN ("Files.Read", "Files.Read.All", "Files.ReadWrite", "Files.ReadWrite.All", "Files.ReadWrite.AppFolder") 
| stats max(_time) as lastTime values(Scope) by Operation, user, object, ObjectId 
| `security_content_ctime(lastTime)` 
| `o365_file_permissioned_application_consent_granted_by_user_filter`

Macros

The SPL above uses the following Macros:

:information_source: o365_file_permissioned_application_consent_granted_by_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
  • ResultStatus
  • ModifiedProperties{}.NewValue
  • 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

OAuth applications that require file permissions may be legitimate, investigate and filter as needed.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
40.0 80 50 User $user$ consented an OAuth application that requests file-related permissions.

: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