Name:Windows InstallUtil Remote Network Connection id:4fbf9270-43da-11ec-9486-acde48001122 version:13 date:2025-04-22 author:Michael Haag, Splunk status:production type:TTP Description:The following analytic detects the Windows InstallUtil.exe binary making a remote network connection. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on process and network telemetry. This activity is significant because InstallUtil.exe can be exploited to download and execute malicious code, bypassing application control mechanisms. If confirmed malicious, an attacker could achieve code execution, potentially leading to further system compromise, data exfiltration, or lateral movement within the network. Analysts should review the parent process, network connections, and any associated file modifications to determine the legitimacy of this activity. Data_source:
| rename src as dest] | table _time user src dest parent_process_name process_name process_path process process_id dest_port command_and_control | stats count min(_time) as firstTime max(_time) as lastTime values(process) as process values(command_and_control) as command_and_control by user dest process_name process_id dest_port parent_process_name | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`| `windows_installutil_remote_network_connection_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:Limited false positives should be present as InstallUtil is not typically used to download remote files. Filter as needed based on Developers requirements. References: -https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1218.004/T1218.004.md drilldown_searches: name:'View the detection results for - "$user$" and "$dest$"' search:'%original_detection_search% | search user = "$user$" dest = "$dest$"' earliest_offset:'$info_min_time$' latest_offset:'$info_max_time$' name:'View risk events for the last 7 days for - "$user$" and "$dest$"' search:'| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$user$", "$dest$") 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: - 'Living Off The Land' - 'Compromised Windows Host' - 'Signed Binary Proxy Execution InstallUtil' asset_type:Endpoint mitre_attack_id: - 'T1218.004' product: - 'Splunk Enterprise' - 'Splunk Enterprise Security' - 'Splunk Cloud' security_domain:endpoint
