Name:DLLHost with no Command Line Arguments with Network id:f1c07594-a141-11eb-8407-acde48001122 version:12 date:2025-06-10 author:Steven Dick, Michael Haag, Splunk status:production type:TTP Description:The following analytic detects instances of DLLHost.exe running without command line arguments while establishing a network connection. This behavior is identified using Endpoint Detection and Response (EDR) telemetry, focusing on process execution and network activity data. It is significant because DLLHost.exe typically runs with specific arguments, and its absence can indicate malicious activity, such as Cobalt Strike usage. If confirmed malicious, this activity could allow attackers to execute code, move laterally, or exfiltrate data, posing a severe threat to the network's security. Data_source:
-Sysmon EventID 1 AND Sysmon EventID 3
search:| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Processes where Processes.process_name=dllhost.exe Processes.action!="blocked" by host _time span=1h 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)` | regex process="(?i)(dllhost\.exe.{0,4}$)" | rename dest as src | join host process_id [| tstats `security_content_summariesonly` count latest(All_Traffic.dest) as dest latest(All_Traffic.dest_ip) as dest_ip latest(All_Traffic.dest_port) as dest_port FROM datamodel=Network_Traffic.All_Traffic where All_Traffic.dest_port != 0 by host All_Traffic.action All_Traffic.app All_Traffic.bytes All_Traffic.bytes_in All_Traffic.bytes_out All_Traffic.dest All_Traffic.dest_ip All_Traffic.dest_port All_Traffic.dvc All_Traffic.protocol All_Traffic.protocol_version All_Traffic.src All_Traffic.src_ip All_Traffic.src_port All_Traffic.transport All_Traffic.user All_Traffic.vendor_product All_Traffic.direction All_Traffic.process_id | `drop_dm_object_name(All_Traffic)`] | `dllhost_with_no_command_line_arguments_with_network_filter`
how_to_implement:The detection is based on data that originates from Endpoint Detection and Response (EDR) agents. These agents are designed to provide security-related telemetry from the endpoints where the agent is installed. To implement this search, you must ingest logs that contain the process GUID, process name, and parent process. Additionally, you must ingest complete command-line executions. These logs must be processed using the appropriate Splunk Technology Add-ons that are specific to the EDR product. The logs must also be mapped to the `Processes` node of the `Endpoint` data model. Use the Splunk Common Information Model (CIM) to normalize the field names and speed up the data modeling process. known_false_positives:Although unlikely, some legitimate third party applications may use a moved copy of dllhost, triggering a false positive. References: -https://raw.githubusercontent.com/threatexpress/malleable-c2/c3385e481159a759f79b8acfe11acf240893b830/jquery-c2.4.2.profile -https://www.cobaltstrike.com/blog/learn-pipe-fitting-for-all-of-your-offense-projects/ drilldown_searches: name:'View the detection results for - "$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$") starthoursago=168 | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`' earliest_offset:'$info_min_time$' latest_offset:'$info_max_time$' tags: analytic_story: - 'BlackByte Ransomware' - 'Cobalt Strike' - 'Graceful Wipe Out Attack' - 'Cactus Ransomware' - 'Storm-2460 CLFS Zero Day Exploitation' - 'Earth Alux' asset_type:Endpoint mitre_attack_id: - 'T1055' product: - 'Splunk Enterprise' - 'Splunk Enterprise Security' - 'Splunk Cloud' security_domain:endpoint
