Name:System User Discovery With Whoami id:894fc43e-6f50-47d5-a68b-ee9ee23e18f4 version:3 date:2024-10-17 author:Mauricio Velazco, Splunk status:production type:Hunting Description:The following analytic detects the execution of `whoami.exe` without any arguments. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on process execution logs. This activity is significant because both Red Teams and adversaries use `whoami.exe` to identify the current logged-in user, aiding in situational awareness and Active Directory discovery. If confirmed malicious, this behavior could indicate an attacker is gathering information to further compromise the system, potentially leading to privilege escalation or lateral movement within the network. Data_source:
-Sysmon EventID 1
-Windows Event Log Security 4688
-CrowdStrike ProcessRollup2
search:| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where (Processes.process_name="whoami.exe") by Processes.dest Processes.user Processes.parent_process Processes.process_name Processes.process Processes.process_id Processes.parent_process_id | `drop_dm_object_name(Processes)` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `system_user_discovery_with_whoami_filter`
how_to_implement:The detection is based on data that originates from Endpoint Detection and Response (EDR) agents. These agents are designed to provide security-related telemetry from the endpoints where the agent is installed. To implement this search, you must ingest logs that contain the process GUID, process name, and parent process. Additionally, you must ingest complete command-line executions. These logs must be processed using the appropriate Splunk Technology Add-ons that are specific to the EDR product. The logs must also be mapped to the `Processes` node of the `Endpoint` data model. Use the Splunk Common Information Model (CIM) to normalize the field names and speed up the data modeling process. known_false_positives:Administrators or power users may use this command for troubleshooting. References: -https://attack.mitre.org/techniques/T1033/ drilldown_searches:
: tags: analytic_story: - 'Winter Vivern' - 'Active Directory Discovery' - 'Rhysida Ransomware' - 'Qakbot' - 'CISA AA23-347A' asset_type:Endpoint confidence:50 impact:30 message:System user discovery on $dest$ mitre_attack_id: - 'T1033' observable: name:'dest' type:'Endpoint' - role: - 'Victim' product: - 'Splunk Enterprise' - 'Splunk Enterprise Security' - 'Splunk Cloud' required_fields: - '_time' - 'Processes.dest' - 'Processes.user' - 'Processes.parent_process_name' - 'Processes.parent_process' - 'Processes.original_file_name' - 'Processes.process_name' - 'Processes.process' - 'Processes.process_id' - 'Processes.parent_process_path' - 'Processes.process_path' - 'Processes.parent_process_id' risk_score:15 security_domain:endpoint
