Name:O365 Email Security Feature Changed id:4d28013d-3a0f-4d65-a33f-4e8009fee0ae version:2 date:2024-09-30 author:Steven Dick status:production type:TTP 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. Data_source:
-O365 Universal Audit Log
search:`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`
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. References: -https://learn.microsoft.com/en-us/entra/fundamentals/security-defaults -https://attack.mitre.org/techniques/T1562/008/ drilldown_searches: name:'View the detection results for - "$user$"' search:'%original_detection_search% | search user = "$user$"' earliest_offset:'$info_min_time$' latest_offset:'$info_max_time$' name:'View risk events for the last 7 days for - "$user$"' search:'| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$user$") starthoursago=168 | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`' earliest_offset:'$info_min_time$' latest_offset:'$info_max_time$' tags: analytic_story: - 'Office 365 Persistence Mechanisms' - 'Office 365 Account Takeover' asset_type:O365 Tenant confidence:25 impact:100 message:An O365 security object [$object$] was altered by user $user$ using $signature$ mitre_attack_id: - 'T1562' - 'T1562.008' - 'T1562.001' observable: name:'user' type:'User' - role: - 'Victim' product: - 'Splunk Enterprise' - 'Splunk Enterprise Security' - 'Splunk Cloud' required_fields: - '_time' - 'Id' - 'UserId' - 'Operation' - 'Workload' risk_score:25 security_domain:threat
