Detection: O365 Privileged Graph API Permission Assigned

Updated Date: 2024-09-30 ID: 868f3131-d5e1-4bf1-af5b-9b0fbaaaedbb Author: Mauricio Velazco, Splunk Type: TTP Product: Splunk Enterprise Security

Description

The following analytic detects the assignment of critical Graph API permissions in Azure AD using the O365 Unified Audit Log. It focuses on permissions such as Application.ReadWrite.All, AppRoleAssignment.ReadWrite.All, and RoleManagement.ReadWrite.Directory. The detection method leverages Azure Active Directory workload events, specifically 'Update application' operations. This activity is significant as these permissions provide extensive control over Azure AD settings, posing a high risk if misused. If confirmed malicious, this could allow unauthorized modifications, leading to potential data breaches or privilege escalation. Immediate investigation is crucial.

Search

1`o365_management_activity` Workload=AzureActiveDirectory Operation="Update application." 
2| eval newvalue = mvindex('ModifiedProperties{}.NewValue',0) 
3| spath input=newvalue  
4| search "{}.RequiredAppPermissions{}.EntitlementId"="1bfefb4e-e0b5-418b-a88f-73c46d2cc8e9" OR "{}.RequiredAppPermissions{}.EntitlementId"="06b708a9-e830-4db3-a914-8e69da51d44f" OR "{}.RequiredAppPermissions{}.EntitlementId"="9e3f62cf-ca93-4989-b6ce-bf83c28f9fe8"  
5| eval Permissions = '{}.RequiredAppPermissions{}.EntitlementId' 
6| stats count earliest(_time) as firstTime latest(_time) as lastTime values(Permissions) by user, object, user_agent, Operation 
7| `security_content_ctime(firstTime)` 
8| `security_content_ctime(lastTime)` 
9| `o365_privileged_graph_api_permission_assigned_filter`

Data Source

Name	Platform	Sourcetype	Source
O365 Update application.	N/A	`'o365:management:activity'`	`'o365'`

Macros Used

Name	Value
o365_management_activity	`sourcetype=o365:management:activity`
o365_privileged_graph_api_permission_assigned_filter	`search *`

o365_privileged_graph_api_permission_assigned_filter is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Annotations

- MITRE ATT&CK

+ Kill Chain Phases

+ NIST

+ CIS

- Threat Actors

ID	Technique	Tactic
T1003.002	Security Account Manager	Credential Access

KillChainPhase.EXPLOITAITON

NistCategory.DE_CM

Cis18Value.CIS_10

APT29

APT41

APT5

Agrius

Daggerfly

Dragonfly

Ember Bear

FIN13

GALLIUM

Ke3chang

Threat Group-3390

Wizard Spider

menuPass

Default Configuration

This detection is configured by default in Splunk Enterprise Security to run with the following settings:

Setting	Value
Disabled	true
Cron Schedule	`0 * * * *`
Earliest Time	`-70m@m`
Latest Time	`-10m@m`
Schedule Window	`auto`
Creates Notable	Yes
Rule Title	`%name%`
Rule Description	`%description%`
Notable Event Fields	user, dest
Creates Risk Event	True

This configuration file applies to all detections of type TTP. These detections will use Risk Based Alerting and generate Notable Events.

Implementation

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

Known False Positives

Privileged Graph API permissions may be assigned for legitimate purposes. Filter as needed.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message	Risk Score	Impact	Confidence
User $user$ assigned privileged Graph API permissions to $object$	54	90	60

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

References

Detection Testing

Test Type	Status	Dataset	Source	Sourcetype
Validation	✅ Passing	N/A	N/A	N/A
Unit	✅ Passing	Dataset	`o365`	`o365:management:activity`
Integration	✅ Passing	Dataset	`o365`	`o365:management:activity`

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: GitHub | Version: 3