Detection rules › Splunk
System User Discovery With Whoami
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.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Discovery | T1033 System Owner/User Discovery |
Event coverage
| Provider | Event | Title |
|---|---|---|
| Sysmon | Event ID 1 | Process creation |
| Security-Auditing | Event ID 4688 | A new process has been created. |
Rule body splunk
name: System User Discovery With Whoami
id: 894fc43e-6f50-47d5-a68b-ee9ee23e18f4
version: 11
creation_date: '2021-08-24'
modification_date: '2026-05-13'
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"
OR
Processes.process_original_file_name="whoami.exe"
)
BY Processes.action Processes.dest Processes.original_file_name
Processes.parent_process Processes.parent_process_exec Processes.parent_process_guid
Processes.parent_process_id Processes.parent_process_name Processes.parent_process_path
Processes.process Processes.process_exec Processes.process_guid
Processes.process_hash Processes.process_id Processes.process_integrity_level
Processes.process_name Processes.process_path Processes.user
Processes.user_id Processes.vendor_product
| `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/
analytic_story:
- Winter Vivern
- Active Directory Discovery
- Rhysida Ransomware
- Qakbot
- CISA AA23-347A
- PHP-CGI RCE Attack on Japanese Organizations
- LAMEHUG
- Lotus Blossom Chrysalis Backdoor
asset_type: Endpoint
mitre_attack_id:
- T1033
product:
- Splunk Enterprise
- Splunk Enterprise Security
- Splunk Cloud
category: endpoint
security_domain: endpoint
tests:
- name: True Positive Test
attack_data:
- data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1033/AD_discovery/windows-sysmon.log
source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
sourcetype: XmlWinEventLog
test_type: unit
Stages and Predicates
Stage 1: tstats
| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Processes
WHERE (
Processes.process_name="whoami.exe"
OR
Processes.process_original_file_name="whoami.exe"
)
BY Processes.action Processes.dest Processes.original_file_name
Processes.parent_process Processes.parent_process_exec Processes.parent_process_guid
Processes.parent_process_id Processes.parent_process_name Processes.parent_process_path
Processes.process Processes.process_exec Processes.process_guid
Processes.process_hash Processes.process_id Processes.process_integrity_level
Processes.process_name Processes.process_path Processes.user
Processes.user_id Processes.vendor_product
Stage 2: search
| `drop_dm_object_name(Processes)`
Stage 3: search
| `security_content_ctime(firstTime)`
Stage 4: search
| `security_content_ctime(lastTime)`
Stage 5: search
| `system_user_discovery_with_whoami_filter`
Indicators
Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.
| Field | Kind | Values |
|---|---|---|
Processes.process_name | eq |
|
Processes.process_original_file_name | eq |
|