Detection: O365 User Consent Denied for OAuth Application

Updated Date: 2026-05-13 ID: 2d8679ef-b075-46be-8059-c25116cb1072 Author: Mauricio Velazco, Splunk Type: TTP Product: Splunk Enterprise Security

Description

The following analytic identifies instances where a user has denied consent to an OAuth application seeking permissions within the Office 365 environment. This detection leverages O365 audit logs, focusing on events related to user consent actions. By filtering for denied consent actions associated with OAuth applications, it captures instances where users have actively rejected permission requests. This activity is significant as it may indicate users spotting potentially suspicious or unfamiliar applications. If confirmed malicious, it suggests an attempt by a potentially harmful application to gain unauthorized access, which was proactively blocked by the user.

Search

 1`o365_graph` status.errorCode=65004
 2  
 3| rename userPrincipalName as user
 4  
 5| rename ipAddress as src_ip
 6  
 7| stats min(_time) as firstTime max(_time) as lastTime
 8    BY user src_ip appDisplayName
 9       status.failureReason
10  
11| `security_content_ctime(firstTime)`
12  
13| `security_content_ctime(lastTime)`
14  
15| `o365_user_consent_denied_for_oauth_application_filter`

Data Source

Name	Platform	Sourcetype	Source
O365	Other	`'o365:management:activity'`	`'o365'`

Macros Used

Name	Value
security_content_ctime	`convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$)`
o365_user_consent_denied_for_oauth_application_filter	`search *`

o365_user_consent_denied_for_oauth_application_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
T1528	Steal Application Access Token	Credential Access

Exploitation

DE.CM

CIS 10

APT29

Leviathan

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 Finding (Notable)	Yes
Rule Title	`%name%`
Rule Description	`%description%`
Notable Event Fields	user, dest
Creates Intermediate Finding (Risk Event)	No

TTP detections generate a Finding (Notable) and may generate Intermediate Findings (Risk Events) for associated entities.

Implementation

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

Known False Positives

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

Associated Analytic Story

Office 365 Account Takeover

Finding

Title	Entity Field	Entity Type	Risk Score
User $user$ denifed consent for an OAuth application.	user	user	50

Threat Objects

Field	Type
src_ip	ip_address

References

Detection Testing

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

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: 11