splunk-security_content/docs/_posts/2021-05-20-cmd_echo_pipe_-_escalation.md

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title	excerpt	categories	last_modified_at	toc	toc_label	tags
CMD Echo Pipe - Escalation	Command and Scripting Interpreter , Windows Command Shell , Windows Service , Create or Modify System Process	Endpoint	2021-05-20	true		Command and Scripting Interpreter Windows Command Shell Windows Service Create or Modify System Process Execution Execution Persistence Privilege Escalation Persistence Privilege Escalation Splunk Enterprise Splunk Enterprise Security Splunk Cloud Endpoint

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Description

This analytic identifies a common behavior by Cobalt Strike and other frameworks where the adversary will escalate privileges, either via jump (Cobalt Strike PTH) or getsystem, using named-pipe impersonation. A suspicious event will look like cmd.exe /c echo 4sgryt3436 > \\.\Pipe\5erg53.

• Type: TTP
• Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
• Datamodel: Endpoint- Datasource: Splunk Add-on for Sysmon
• Last Updated: 2021-05-20
• Author: Michael Haag, Splunk
• ID: eb277ba0-b96b-11eb-b00e-acde48001122

Annotations

ATT&CK

ID	Technique	Tactic
T1059	Command and Scripting Interpreter	Execution

| T1059.003 | Windows Command Shell | Execution |

| T1543.003 | Windows Service | Persistence, Privilege Escalation |

| T1543 | Create or Modify System Process | Persistence, Privilege Escalation |

Kill Chain Phase

• Exploitation

NIST

CIS20

CVE

Search

| 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.process_name Processes.original_file_name Processes.process Processes.process_id Processes.parent_process_id 
| `drop_dm_object_name(Processes)` 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `cmd_echo_pipe___escalation_filter`

Macros

The SPL above uses the following Macros:

• process_cmd
• security_content_ctime
• security_content_summariesonly

ℹ️ cmd_echo_pipe_-_escalation_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required field

• _time
• Processes.dest
• Processes.user
• Processes.parent_process_name
• Processes.parent_process
• Processes.original_file_name
• Processes.process_name
• Processes.process
• Processes.process_id
• Processes.parent_process_path
• Processes.process_path
• Processes.parent_process_id

How To Implement

To successfully implement this search you need to be ingesting information on process that include the name of the process responsible for the changes from your endpoints into the Endpoint datamodel in the Processes node. In addition, confirm the latest CIM App 4.20 or higher is installed and the latest TA for the endpoint product.

Known False Positives

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

Associated Analytic story

• Cobalt Strike

RBA

Risk Score	Impact	Confidence	Message
64.0	80	80	An instance of parent_process_name spawning process_name was identified on endpoint dest by user user potentially performing privilege escalation using named pipes related to Cobalt Strike and other frameworks.

ℹ️ The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

Reference

• https://redcanary.com/threat-detection-report/threats/cobalt-strike/
• https://github.com/rapid7/meterpreter/blob/master/source/extensions/priv/server/elevate/namedpipe.c

Test Dataset

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

• https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1055/cobalt_strike/windows-sysmon.log

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