Detection: SearchProtocolHost with no Command Line with Network

Updated Date: 2026-01-01 ID: b690df8c-a145-11eb-a38b-acde48001122 Author: Michael Haag, Splunk Type: TTP Product: Splunk Enterprise Security

Description

The following analytic detects instances of searchprotocolhost.exe running without command line arguments but with an active network connection. This behavior is identified using Endpoint Detection and Response (EDR) telemetry, focusing on process execution and network traffic data. It is significant because searchprotocolhost.exe typically runs with specific command line arguments, and deviations from this norm can indicate malicious activity, such as Cobalt Strike usage. If confirmed malicious, this activity could allow attackers to establish network connections for command and control, potentially leading to data exfiltration or further system compromise.

Search

 1
 2| tstats `security_content_summariesonly` count FROM datamodel=Endpoint.Processes where
 3(
 4  Processes.process_name=searchprotocolhost.exe
 5  OR
 6  Processes.original_file_name=searchprotocolhost.exe
 7)
 8Processes.process IN (
 9  "*searchprotocolhost",
10  "*searchprotocolhost.exe",
11  "*searchprotocolhost.exe\""
12)
13by _time span=1h Processes.action Processes.dest Processes.original_file_name
14   Processes.parent_process Processes.parent_process_exec Processes.parent_process_guid
15   Processes.parent_process_id Processes.parent_process_name Processes.parent_process_path
16   Processes.process Processes.process_exec Processes.process_guid Processes.process_hash
17   Processes.process_id Processes.process_integrity_level Processes.process_name Processes.process_path
18   Processes.user Processes.user_id Processes.vendor_product
19
20| `drop_dm_object_name(Processes)`
21
22| `security_content_ctime(firstTime)`
23
24| `security_content_ctime(lastTime)`
25
26| join  process_id
27[
28  
29| tstats `security_content_summariesonly` count
30    FROM datamodel=Network_Traffic.All_Traffic where
31    All_Traffic.dest_port != 0
32    by All_Traffic.action All_Traffic.app All_Traffic.bytes All_Traffic.bytes_in All_Traffic.bytes_out
33       All_Traffic.dest  All_Traffic.dest_ip All_Traffic.dest_port All_Traffic.dvc All_Traffic.protocol
34       All_Traffic.protocol_version All_Traffic.src All_Traffic.src_ip All_Traffic.src_port
35       All_Traffic.transport All_Traffic.user All_Traffic.vendor_product All_Traffic.direction
36       All_Traffic.process_id
37
38| `drop_dm_object_name(All_Traffic)`
39
40| rename dest as C2
41]
42
43| table _time dest parent_process_name process_name process_path process process_id dest_port C2
44
45| `searchprotocolhost_with_no_command_line_with_network_filter`

Data Source

Name	Platform	Sourcetype	Source
Sysmon EventID 1	Windows	`'XmlWinEventLog'`	`'XmlWinEventLog:Microsoft-Windows-Sysmon/Operational'`
Sysmon EventID 3	Windows	`'XmlWinEventLog'`	`'XmlWinEventLog:Microsoft-Windows-Sysmon/Operational'`

Macros Used

Name	Value
security_content_ctime	`convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$)`
searchprotocolhost_with_no_command_line_with_network_filter	`search *`

searchprotocolhost_with_no_command_line_with_network_filter is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Annotations

- MITRE ATT&CK

+ Kill Chain Phases

+ NIST

+ CIS

- Threat Actors

ID	Technique	Tactic
T1055	Process Injection	Defense Evasion

Exploitation

DE.CM

CIS 10

Default Configuration

This detection is configured by default in Splunk Enterprise Security to run with the following settings:

Setting	Value
Disabled	true
Cron Schedule	`0 * * * *`
Earliest Time	`-70m@m`
Latest Time	`-10m@m`
Schedule Window	`auto`
Creates Notable	Yes
Rule Title	`%name%`
Rule Description	`%description%`
Notable Event Fields	user, dest
Creates Risk Event	True

This configuration file applies to all detections of type TTP. These detections will use Risk Based Alerting and generate Notable Events.

Implementation

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 may be present in small environments. Tuning may be required based on parent process.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message:

A searchprotocolhost.exe process $process_name$ with no commandline on host $dest$

Risk Object	Risk Object Type	Risk Score	Threat Objects
dest	system	70	process_name

References

https://github.com/mandiant/red_team_tool_countermeasures/blob/master/rules/PGF/supplemental/hxioc/SUSPICIOUS%20EXECUTION%20OF%20SEARCHPROTOCOLHOST%20(METHODOLOGY).ioc

Detection Testing

Test Type	Status	Dataset	Source	Sourcetype
Validation	✅ Passing	N/A	N/A	N/A
Unit	✅ Passing	Dataset	`XmlWinEventLog:Microsoft-Windows-Sysmon/Operational`	`XmlWinEventLog`
Integration	✅ Passing	Dataset	`XmlWinEventLog:Microsoft-Windows-Sysmon/Operational`	`XmlWinEventLog`

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

Source: GitHub | Version: 12