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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.

  • Type: TTP
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Risk
  • Last Updated: 2024-05-26
  • Author: Mauricio Velazco, Splunk
  • ID: 242e4d30-cb59-4051-b0cf-58895e218f40

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=Failure 
| eval permissions =mvindex('ModifiedProperties{}.NewValue', 4) 
| eval reason =mvindex('ModifiedProperties{}.NewValue', 5) 
|  search reason = "Risky application detected" 
| rex field=permissions "Scope: (?<Scope>[^,]+)" 
|  stats max(_time) as lastTime by Operation, user, reason, object, Scope 
| `security_content_ctime(lastTime)` 
| `o365_user_consent_blocked_for_risky_application_filter`

Macros

The SPL above uses the following Macros:

:information_source: o365_user_consent_blocked_for_risky_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
  • 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

Microsofts algorithm to identify risky applications is unknown and may flag legitimate applications.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
30.0 30 100 O365 has blocked $user$ attempt to grant to consent to an application deemed risky.

: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