Zeek SMB spoolss Named Pipe (IPC$) Access

Flags Zeek SMB events accessing the spoolss named pipe via IPC$.

FreeReviewedSigma · Medium · v2

Product: zeek
Service: smb_files
Author: OTR (Open Threat Research), @neu5ron (SigmaHQ), DRL 1.1
Published: 2018-11-28
Updated: 2026-07-31

ATT&CK techniques

Lateral Movement

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
- T1021.002SMB/Windows Admin Shares
Collection
C2
Exfiltration
Impact

What it detects

This rule flags SMB file activity where the name field is "spoolss" and the path ends with "IPC$", indicating attempts to access the spoolss named pipe over the SMB IPC share. Attackers can use this to provoke network authentication from systems that expose the spool service, which can facilitate lateral movement or follow-on abuse. It relies on Zeek SMB file logs capturing both the IPC$-scoped path and the spoolss pipe name.

Reporting behind it

Related detections9 linkedT1021.002 — drag to rearrange

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Suspicious Impacket smbexec Command Execution Pattern

Malicious Impacket Wmiexec Remote Command Execution Pattern

Suspicious Remote Admin Share Execution via Conhost

Malicious Network Share Manipulation via Commandline (via process_creation)

Suspicious Number of Oustanding SMB Requests Increased (via process_creation)

Suspicious SMB Insecure Guest Authentication Activated - Native (via security)

Suspicious PSexec Execution Over SMB Share (via security)

Suspicious Permissions Modification on a Network Share (via security)

Zeek SMB spoolss Named Pipe (IPC$) Access

Pivot detection · T1021.002 · 9 related

Changelog

v2
Candidate ingested via manual entry.2026-07-31
v1
No changelog recorded for this version.2026-07-30

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.

zeek-smb-files-spoolss-named-pipe-access-via-ipc-bae2865c

title: Zeek SMB spoolss Named Pipe (IPC$) Access
id: 7e9689f4-e12a-4065-8f3b-8259145e1e0c
status: test
description: This rule flags SMB file activity where the name field is "spoolss" and the path ends with "IPC$", indicating attempts to access the spoolss named pipe over the SMB IPC share. Attackers can use this to provoke network authentication from systems that expose the spool service, which can facilitate lateral movement or follow-on abuse. It relies on Zeek SMB file logs capturing both the IPC$-scoped path and the spoolss pipe name.
references:
  - https://posts.specterops.io/hunting-in-active-directory-unconstrained-delegation-forests-trusts-71f2b33688e1
  - https://dirkjanm.io/a-different-way-of-abusing-zerologon/
  - https://twitter.com/_dirkjan/status/1309214379003588608
  - https://github.com/SigmaHQ/sigma/blob/master/rules/network/zeek/zeek_dce_rpc_smb_spoolss_named_pipe.yml
author: OTR (Open Threat Research), @neu5ron, Huntrule Team
date: 2018-11-28
modified: 2022-10-09
tags:
  - attack.lateral-movement
  - attack.t1021.002
logsource:
  product: zeek
  service: smb_files
detection:
  selection:
    path|endswith: IPC$
    name: spoolss
  condition: selection
falsepositives:
  - Domain Controllers that are sometimes, commonly although should not be, acting as printer servers too
level: medium
license: DRL-1.1
related:
  - id: bae2865c-5565-470d-b505-9496c87d0c30
    type: derived

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