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Description

The following analytic identifies when specific O365 advanced security settings are altered within the Office 365 tenant. If an attacker successfully disables O365 security settings, they can operate within the tenant with reduced risk of detection. This can lead to unauthorized data access, data exfiltration, account compromise, or other malicious activities without leaving a detailed audit trail.

  • Type: TTP

  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud

  • Last Updated: 2024-04-01
  • Author: Steven Dick
  • ID: 4d28013d-3a0f-4d65-a33f-4e8009fee0ae

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1562 Impair Defenses Defense Evasion
T1562.008 Disable or Modify Cloud Logs Defense Evasion
T1562.001 Disable or Modify Tools Defense Evasion
Kill Chain Phase
  • Exploitation
NIST
  • DE.CM
CIS20
  • CIS 10
CVE 


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`o365_management_activity` Workload=Exchange AND Operation IN ("Set-*","Disable-*","New-*","Remove-*") Operation IN ("*AntiPhish*","*SafeLink*","*SafeAttachment*","*Malware*") 
| stats values(ObjectId) as object, min(_time) as firstTime, max(_time) as lastTime, count  by Id, UserId, Operation 
| rename Id as object_id, UserId as user, Operation as signature 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `o365_email_security_feature_changed_filter`

Macros

The SPL above uses the following Macros:

:information_source: o365_email_security_feature_changed_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
  • Id
  • UserId
  • Operation
  • Workload

How To Implement

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

Known False Positives

Administrators might alter features for troubleshooting, performance reasons, or other administrative tasks. Filter as needed.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
25.0 100 25 An O365 security object [$object$] was altered by user $user$ using $signature$

: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: 1