Name:ASL AWS New MFA Method Registered For User id:33ae0931-2a03-456b-b1d7-b016c5557fbd version:14 date:None author:Patrick Bareiss, Splunk status:production type:TTP Description:The following analytic identifies the registration of a new Multi-Factor Authentication (MFA) method for an AWS account, as logged through Amazon Security Lake (ASL). It detects this activity by monitoring the `CreateVirtualMFADevice` API operation within ASL logs. This behavior is significant because adversaries who gain unauthorized access to an AWS account may register a new MFA method to maintain persistence. If confirmed malicious, this activity could allow attackers to secure their access, making it harder to detect and remove their presence from the compromised environment. Data_source:
| stats count min(_time) as firstTime max(_time) as lastTime BY actor.user.uid api.operation api.service.name http_request.user_agent src_endpoint.ip actor.user.account.uid cloud.provider cloud.region
| rename actor.user.uid as user api.operation as action api.service.name as dest http_request.user_agent as user_agent src_endpoint.ip as src actor.user.account.uid as vendor_account cloud.provider as vendor_product cloud.region as vendor_region
how_to_implement:The detection is based on Amazon Security Lake events from Amazon Web Services (AWS), which is a centralized data lake that provides security-related data from AWS services. To use this detection, you must ingest CloudTrail logs from Amazon Security Lake into Splunk. To run this search, ensure that you ingest events using the latest version of Splunk Add-on for Amazon Web Services (https://splunkbase.splunk.com/app/1876) or the Federated Analytics App. known_false_positives:Newly onboarded users who are registering an MFA method for the first time will also trigger this detection. References: -https://aws.amazon.com/blogs/security/you-can-now-assign-multiple-mfa-devices-in-iam/ -https://attack.mitre.org/techniques/T1556/ -https://attack.mitre.org/techniques/T1556/006/ -https://twitter.com/jhencinski/status/1618660062352007174 drilldown_searches: name:'View the detection results for - "$dest$"' search:'%original_detection_search% | search dest = "$dest$"' earliest_offset:'$info_min_time$' latest_offset:'$info_max_time$' name:'View risk events for the last 7 days for - "$dest$"' search:'| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$dest$") | 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:['AWS Identity and Access Management Account Takeover']
