Detection: Windows PUA Named Pipe

Description

The following analytic detects the creation or connection to named pipes used by potentially unwanted applications (PUAs) like VPNs or utilities like PsExec. It leverages Sysmon EventCodes 17 and 18. If confirmed malicious, this could allow an attacker to abuse these to potentially gain persistence, command and control, or further system compromise.

Search

 1`sysmon`
 2(EventCode=17 OR EventCode=18)
 3NOT process_path IN (
 4  "*:\\Program Files \(x86\)\\Adobe*",
 5  "*:\\Program Files \(x86\)\\Google*",
 6  "*:\\Program Files \(x86\)\\Microsoft*",
 7  "*:\\Program Files\\Adobe*",
 8  "*:\\Program Files\\dotnet\\dotnet.exe",
 9  "*:\\Program Files\\Google*",
10  "*:\\Program Files\\Microsoft*",
11  "*:\\Windows\\system32\\SearchIndexer.exe",
12  "*:\\Windows\\System32\\svchost.exe",
13  "*:\\Windows\\SystemApps\\Microsoft*",
14  "*\\Amazon\\SSM\\Instance*",
15  "*\\AppData\\Local\\Google*",
16  "*\\AppData\\Local\\Kingsoft\\*",
17  "*\\AppData\\Local\\Microsoft*",
18  "System"
19)
20
21
22| stats  min(_time) as firstTime max(_time) as lastTime
23count by dest dvc process_exec process_guid process_id process_path signature signature_id 
24vendor_product pipe_name user_id Image process_name
25
26
27| lookup pua_named_pipes pua_pipe_name AS pipe_name OUTPUT tool, description
28
29| where isnotnull(tool)
30
31| `security_content_ctime(firstTime)`
32
33| `security_content_ctime(lastTime)`
34
35| `windows_pua_named_pipe_filter`

Data Source

Name	Platform	Sourcetype	Source
Sysmon EventID 17	Windows	'XmlWinEventLog'	'XmlWinEventLog:Microsoft-Windows-Sysmon/Operational'
Sysmon EventID 18	Windows	'XmlWinEventLog'	'XmlWinEventLog:Microsoft-Windows-Sysmon/Operational'

Macros Used

Annotations

Default Configuration

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

Implementation

To successfully implement this search, you need to be ingesting logs with the process name and pipename from your endpoints. If you are using Sysmon, you must have at least version 6.0.4 of the Sysmon TA.

Known False Positives

PUAs can be used in a legitimate manner. Therefore, some of the named pipes identified and added may cause false positives. Filter by process name or pipe name to reduce false positives.

Associated Analytic Story

• Active Directory Lateral Movement

• BlackByte Ransomware

• CISA AA22-320A

• Cactus Ransomware

• DHS Report TA18-074A

• DarkGate Malware

• DarkSide Ransomware

• HAFNIUM Group

• IcedID

• Medusa Ransomware

• Rhysida Ransomware

• SamSam Ransomware

• Sandworm Tools

• Seashell Blizzard

• VanHelsing Ransomware

• Volt Typhoon

Risk Based Analytics (RBA)

Risk Message:

An instance of $process_name$ located in $process_path$ was identified on endpoint $dest$ accessing known named pipe $pipe_name$ from a potentially unwanted application in your environment.

References

• https://attack.mitre.org/techniques/T1218/009/

• https://docs.microsoft.com/en-us/windows/win32/ipc/named-pipes

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: 1