Detection: CMD Echo Pipe - Escalation

Description

The following analytic identifies the use of named-pipe impersonation for privilege escalation, commonly associated with Cobalt Strike and similar frameworks. It detects command-line executions where cmd.exe uses echo to write to a named pipe, such as cmd.exe /c echo 4sgryt3436 > \\.\Pipe\5erg53. This detection leverages data from Endpoint Detection and Response (EDR) agents, focusing on process and command-line telemetry. This activity is significant as it indicates potential privilege escalation attempts. If confirmed malicious, attackers could gain elevated privileges, enabling further compromise and persistence within the environment.

Search

1
2| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where `process_cmd` OR Processes.process=*%comspec%* (Processes.process=*echo* AND Processes.process=*pipe*) by Processes.dest Processes.user Processes.parent_process Processes.parent_process_name Processes.process_name Processes.original_file_name Processes.process Processes.process_id Processes.parent_process_id 
3| `drop_dm_object_name(Processes)` 
4| `security_content_ctime(firstTime)` 
5| `security_content_ctime(lastTime)` 
6| `cmd_echo_pipe___escalation_filter`

Data Source

Name	Platform	Sourcetype	Source
CrowdStrike ProcessRollup2	N/A	'crowdstrike:events:sensor'	'crowdstrike'
Sysmon EventID 1	Windows	'xmlwineventlog'	'XmlWinEventLog:Microsoft-Windows-Sysmon/Operational'
Windows Event Log Security 4688	Windows	'xmlwineventlog'	'XmlWinEventLog:Security'

Macros Used

Annotations

Default Configuration

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

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

Unknown. It is possible filtering may be required to ensure fidelity.

Associated Analytic Story

• BlackByte Ransomware

• Cobalt Strike

• Graceful Wipe Out Attack

Risk Based Analytics (RBA)

References

• https://redcanary.com/threat-detection-report/threats/cobalt-strike/

• https://github.com/rapid7/meterpreter/blob/master/source/extensions/priv/server/elevate/namedpipe.c

Detection Testing

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: 5