ID | Technique | Tactic |
---|---|---|
T1528 | Steal Application Access Token | Credential Access |
Detection: O365 User Consent Blocked for Risky Application
Description
The following analytic identifies instances where Office 365 has blocked a user's attempt to grant consent to an application deemed risky or potentially malicious. This detection leverages O365 audit logs, specifically focusing on failed user consent actions due to system-driven blocks. Monitoring these blocked consent attempts is crucial as it highlights potential threats early on, indicating that a user might be targeted or that malicious applications are attempting to infiltrate the organization. If confirmed malicious, this activity suggests that O365's security measures successfully prevented a harmful application from accessing organizational data, warranting immediate investigation.
Search
1`o365_management_activity` Workload=AzureActiveDirectory Operation="Consent to application." ResultStatus=Failure
2| eval permissions =mvindex('ModifiedProperties{}.NewValue', 4)
3| eval reason =mvindex('ModifiedProperties{}.NewValue', 5)
4| search reason = "Risky application detected"
5| rex field=permissions "Scope: (?<Scope>[^,]+)"
6| stats max(_time) as lastTime by Operation, user, reason, object, Scope
7| `security_content_ctime(lastTime)`
8| `o365_user_consent_blocked_for_risky_application_filter`
Data Source
Name | Platform | Sourcetype | Source | Supported App |
---|---|---|---|---|
O365 Consent to application. | N/A | 'o365:management:activity' |
'o365' |
N/A |
Macros Used
Name | Value |
---|---|
o365_management_activity | sourcetype=o365:management:activity |
o365_user_consent_blocked_for_risky_application_filter | search * |
o365_user_consent_blocked_for_risky_application_filter
is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
Annotations
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 |
Implementation
You must install the Splunk Microsoft Office 365 Add-on and ingest Office 365 management activity events.
Known False Positives
Microsofts algorithm to identify risky applications is unknown and may flag legitimate applications.
Associated Analytic Story
Risk Based Analytics (RBA)
Risk Message | Risk Score | Impact | Confidence |
---|---|---|---|
O365 has blocked $user$ attempt to grant to consent to an application deemed risky. | 30 | 30 | 100 |
References
-
https://learn.microsoft.com/en-us/defender-cloud-apps/investigate-risky-oauth
-
https://www.alteredsecurity.com/post/introduction-to-365-stealer
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: 2