Detection: Windows SSH Proxy Command

Updated Date: 2025-10-16 ID: ac520039-21f1-4567-b528-5b7133dba76f Author: Michael Haag, AJ King, Nasreddine Bencherchali, Splunk, Jesse Hunter, Splunk Community Contributor Type: Anomaly Product: Splunk Enterprise Security

Description

This detection identifies potential abuse of SSH "ProxyCommand" or "LocalCommand" by monitoring for suspicious process execution patterns. Specifically, it looks for instances where ssh.exe (as a parent process) containing "ProxyCommand" or "LocalCommand" in its arguments spawns potentially malicious child processes like mshta, powershell, wscript, or cscript, or processes containing "http" in their command line. This technique can be used by attackers to execute arbitrary commands through SSH proxy configurations, potentially enabling command & control activities or remote code execution. The detection focuses on commonly abused Windows scripting engines and web requests that may indicate malicious activity when spawned through SSH proxy commands.

Search

 1
 2| tstats `security_content_summariesonly`
 3  count min(_time) as firstTime
 4        max(_time) as lastTime
 5
 6from datamodel=Endpoint.Processes where
 7
 8Processes.parent_process_name="ssh.exe"
 9(
10  Processes.parent_process = "*ProxyCommand=*"
11  OR
12  (
13    Processes.parent_process = "* PermitLocalCommand=yes*"
14    Processes.parent_process = "* LocalCommand=*"
15  )
16)
17
18Processes.process IN (
19  "*cscript*",
20  "*http*",
21  "*mshta*",
22  "*powershell*",
23  "*pwsh*",
24  "*wmic*",
25  "*wscript*"
26)
27
28by Processes.action Processes.dest Processes.original_file_name Processes.parent_process Processes.parent_process_exec
29   Processes.parent_process_guid Processes.parent_process_id Processes.parent_process_name Processes.parent_process_path
30   Processes.process Processes.process_exec Processes.process_guid Processes.process_hash Processes.process_id
31   Processes.process_integrity_level Processes.process_name Processes.process_path Processes.user Processes.user_id
32   Processes.vendor_product
33
34
35| `drop_dm_object_name(Processes)`
36
37| `security_content_ctime(firstTime)`
38
39| `security_content_ctime(lastTime)`
40
41| `windows_ssh_proxy_command_filter`

Data Source

Name	Platform	Sourcetype	Source
Sysmon EventID 1	Windows	`'XmlWinEventLog'`	`'XmlWinEventLog:Microsoft-Windows-Sysmon/Operational'`
Windows Event Log Security 4688	Windows	`'XmlWinEventLog'`	`'XmlWinEventLog:Security'`

Macros Used

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

windows_ssh_proxy_command_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
T1572	Protocol Tunneling	Command And Control
T1059.001	PowerShell	Execution
T1105	Ingress Tool Transfer	Command And Control

Command and Control

Installation

DE.AE

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 Risk Event	True

This configuration file applies to all detections of type anomaly. These detections will use Risk Based Alerting.

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

Legitimate use of SSH ProxyCommand or LocalCommand with scripting engines may trigger this detection. Filter as needed based on your environment's normal SSH usage patterns and authorized scripting activities.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message:

Suspicious process execution $process$ detected through SSH $parent_process$ on $dest$ by user $user$

Risk Object	Risk Object Type	Risk Score	Threat Objects
dest	system	60	process_name, parent_process_name
user	user	40	process_name, parent_process_name

References

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: 3