Windows Anonymous Pipe Activity

Status: production
Group by: PipeName, dest, event_type, process_guid, process_id, process_name, signature_id
Author: Teoderick Contreras, Splunk
Source: github.com/splunk/security_content

The following analytic detects the creation or connection of anonymous pipes for inter-process communication (IPC) within a Windows environment. Anonymous pipes are commonly used by legitimate system processes, services, and applications to transfer data between related processes. However, adversaries frequently abuse anonymous pipes to facilitate stealthy process injection, command-and-control (C2) communication, credential theft, or privilege escalation. This detection monitors for unusual anonymous pipe activity, particularly involving non-system processes, unsigned executables, or unexpected parent-child process relationships. While legitimate use cases exist—such as Windows services, software installers, or security tools—unusual or high-frequency anonymous pipe activity should be investigated for potential malware, persistence mechanisms, or lateral movement techniques.

Known false positives

Automation tool might use anonymous pipe for task orchestration or process communication.

MITRE ATT&CK coverage

Tactic	Techniques
Execution	`T1559` Inter-Process Communication

Telemetry coverage

Provider	Record / event type
Sysmon	Event ID 17: PipeEvent (Pipe Created)
Sysmon	Event ID 18: PipeEvent (Pipe Connected)

Rule body

name: Windows Anonymous Pipe Activity
id: ee301e1e-cd81-4011-a911-e5f049b9e3d5
version: 7
creation_date: '2025-02-13'
modification_date: '2026-05-13'
author: Teoderick Contreras, Splunk
status: production
type: Hunting
description: "The following analytic detects the creation or connection of anonymous pipes for inter-process communication (IPC) within a Windows environment. Anonymous pipes are commonly used by legitimate system processes, services, and applications to transfer data between related processes. However, adversaries frequently abuse anonymous pipes to facilitate stealthy process injection, command-and-control (C2) communication, credential theft, or privilege escalation. This detection monitors for unusual anonymous pipe activity, particularly involving non-system processes, unsigned executables, or unexpected parent-child process relationships. While legitimate use cases exist—such as Windows services, software installers, or security tools—unusual or high-frequency anonymous pipe activity should be investigated for potential malware, persistence mechanisms, or lateral movement techniques."
data_source:
    - Sysmon EventID 17
    - Sysmon EventID 18
search: '`sysmon` EventCode IN (17,18) EventType IN ( "CreatePipe", "ConnectPipe") PipeName="*Anonymous Pipe*" NOT( Image IN ("C:\\Program Files*", "C:\\Windows\\system32\\*","C:\\Windows\\syswow64\\*")) | stats  min(_time) as firstTime max(_time) as lastTime count by dest EventCode PipeName ProcessGuid ProcessId Image EventType | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `windows_anonymous_pipe_activity_filter`'
how_to_implement: 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: Automation tool might use anonymous pipe for task orchestration or process communication.
references:
    - https://www.trendmicro.com/en_nl/research/24/k/earth-estries.html
analytic_story:
    - Salt Typhoon
    - China-Nexus Threat Activity
    - SnappyBee
    - Interlock Rat
    - Castle RAT
asset_type: Endpoint
mitre_attack_id:
    - T1559
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: endpoint
security_domain: endpoint

Stages and Predicates

Stage 1: `search`

`sysmon` EventCode IN (17,18) EventType IN ( "CreatePipe", "ConnectPipe") PipeName="*Anonymous Pipe*" NOT( Image IN ("C:\\Program Files*", "C:\\Windows\\system32\\*","C:\\Windows\\syswow64\\*"))

Stage 2: `stats`

| stats  min(_time) as firstTime max(_time) as lastTime count by dest EventCode PipeName ProcessGuid ProcessId Image EventType

Stage 3: `search`

| `security_content_ctime(firstTime)`

Stage 4: `search`

| `security_content_ctime(lastTime)`

Stage 5: `search`

| `windows_anonymous_pipe_activity_filter`

Exclusions

The rule actively suppresses these predicates.

Field	Kind	Excluded values	Search
`Image`	in	`"C:\\Program Files"`, `"C:\\Windows\\system32\\"`, `"C:\\Windows\\syswow64\\*"`	`excludes:Image`

Indicators

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`EventCode`	in	`17` corpus 5 (splunk 4, elastic 1) `18` corpus 6 (splunk 4, chronicle 1, kusto 1)	`field:"EventID" kind:in`
`EventType`	in	`"ConnectPipe"` `"CreatePipe"`	`field:"EventType" kind:in`
`PipeName`	eq	`"Anonymous Pipe"`	`field:"PipeName" kind:eq`