O365 User Consent Denied for OAuth Application
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.
- Type: TTP
-
Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Last Updated: 2024-05-22
- Author: Mauricio Velazco, Splunk
- ID: 2d8679ef-b075-46be-8059-c25116cb1072
Annotations
Kill Chain Phase
- Exploitation
NIST
- DE.CM
CIS20
- CIS 10
CVE
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`o365_graph` status.errorCode=65004
| rename userPrincipalName as user
| rename ipAddress as src_ip
| stats max(_time) as lastTime by user src_ip appDisplayName status.failureReason
| `security_content_ctime(lastTime)`
| `o365_user_consent_denied_for_oauth_application_filter`
Macros
The SPL above uses the following Macros:
o365_user_consent_denied_for_oauth_application_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
- status.errorCode
- userPrincipalName
- ipAddress
- status.failureReason
How To Implement
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
RBA
Risk Score | Impact | Confidence | Message |
---|---|---|---|
30.0 | 30 | 100 | User $user$ denifed consent for an OAuth application. |
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
- https://attack.mitre.org/techniques/T1528/
- https://www.microsoft.com/en-us/security/blog/2022/09/22/malicious-oauth-applications-used-to-compromise-email-servers-and-spread-spam/
- https://learn.microsoft.com/en-us/azure/active-directory/manage-apps/protect-against-consent-phishing
- https://learn.microsoft.com/en-us/defender-cloud-apps/investigate-risky-oauth
- https://www.alteredsecurity.com/post/introduction-to-365-stealer
- https://github.com/AlteredSecurity/365-Stealer
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