Name:Azure AD New MFA Method Registered id:0488e814-eb81-42c3-9f1f-b2244973e3a3 version:12 date:None author:Mauricio Velazco, Splunk status:production type:TTP Description:The following analytic detects the registration of a new Multi-Factor Authentication (MFA) method for a user account in Azure Active Directory. It leverages Azure AD audit logs to identify changes in MFA configurations. This activity is significant because adding a new MFA method can indicate an attacker's attempt to maintain persistence on a compromised account. If confirmed malicious, the attacker could bypass existing security measures, solidify their access, and potentially escalate privileges, access sensitive data, or make unauthorized changes. Immediate verification and remediation are required to secure the affected account. Data_source:
-Azure Active Directory Update user
search:`azure_monitor_aad` operationName="Update user" | rename properties.* as * | eval propertyName = mvindex('targetResources{}.modifiedProperties{}.displayName',0) | search propertyName = StrongAuthenticationMethod | eval oldvalue = mvindex('targetResources{}.modifiedProperties{}.oldValue',0) | eval newvalue = mvindex('targetResources{}.modifiedProperties{}.newValue',0) | rex field=newvalue max_match=0 "(?i)(?<new_method_type>\"MethodType\")" | rex field=oldvalue max_match=0 "(?i)(?<old_method_type>\"MethodType\")" | eval count_new_method_type = coalesce(mvcount(new_method_type), 0) | eval count_old_method_type = coalesce(mvcount(old_method_type), 0) | fillnull | stats count min(_time) as firstTime max(_time) as lastTime by dest user src vendor_account vendor_product newvalue oldvalue signature | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `azure_ad_new_mfa_method_registered_filter`
how_to_implement:You must install the latest version of Splunk Add-on for Microsoft Cloud Services from Splunkbase (https://splunkbase.splunk.com/app/3110/#/details). You must be ingesting Azure Active Directory events into your Splunk environment through an EventHub. This analytic was written to be used with the azure:monitor:aad sourcetype leveraging the AuditLog log category. known_false_positives:Users may register MFA methods legitimally, investigate and filter as needed. References: -https://attack.mitre.org/techniques/T1098/005/ -https://www.microsoft.com/en-us/security/blog/2023/06/08/detecting-and-mitigating-a-multi-stage-aitm-phishing-and-bec-campaign/ -https://www.csoonline.com/article/573451/sophisticated-bec-scammers-bypass-microsoft-365-multi-factor-authentication.html 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 ("$user$") | 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:'7d' latest_offset:'0' analytic_story:['Azure Active Directory Persistence', 'Scattered Lapsus$ Hunters']
