Windows: Detects Access to ADMIN$ Network Share (Event 5140)

Alerts on Windows Security event 5140 entries where an access request targets the ADMIN$ share.

FreeReviewedSigma · Low · v2

Product: windows
Service: security
Author: Florian Roth (Nextron Systems) (SigmaHQ), DRL 1.1
Published: 2017-03-04
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 Windows Security events where a client attempts to access the ADMIN$ hidden administrative network share. Access to ADMIN$ is a common step in Windows lateral movement because it can expose administrative file system paths used for remote control and deployment. Detection relies on audit event 5140 with ShareName set to Admin$ and applies an exclusion for subjects ending with a dollar sign.

Reporting behind it

Related detections9 linkedT1021.002 — drag to rearrange

Malicious WMIexec Style Command Output Redirection to Local Admin Share

Malicious Cobalt Strike Default Named Pipe Activity

Suspicious PsExec Service Launching Encoded PowerShell Payload

Suspicious Impacket Style Command Execution with ADMIN Share Output Redirect

Suspicious Active Directory Reconnaissance via In-Memory Offensive PowerShell (via ps_script)

Suspicious NetExec Post-Exploitation Tool Execution via nxc (via process_creation)

Suspicious SMB Admin Share Mapping for Lateral Tool Transfer (via process_creation)

Suspicious Impacket Remote Execution Tool Usage via process_creation

Suspicious Remote Service Execution via PsExec (via process_creation)

Windows: Detects Access to ADMIN$ Network Share (Event 5140)

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.

windows-security-access-to-admin-network-share-via-event-id-5140-098d7118

title: "Windows: Detects Access to ADMIN$ Network Share (Event 5140)"
id: ac95e4a0-3c5a-4d17-87cd-6411b632b264
status: test
description: This rule flags Windows Security events where a client attempts to access the ADMIN$ hidden administrative network share. Access to ADMIN$ is a common step in Windows lateral movement because it can expose administrative file system paths used for remote control and deployment. Detection relies on audit event 5140 with ShareName set to Admin$ and applies an exclusion for subjects ending with a dollar sign.
references:
  - https://learn.microsoft.com/en-us/previous-versions/windows/it-pro/windows-10/security/threat-protection/auditing/event-5140
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/builtin/security/win_security_admin_share_access.yml
author: Florian Roth (Nextron Systems), Huntrule Team
date: 2017-03-04
modified: 2024-01-16
tags:
  - attack.lateral-movement
  - attack.t1021.002
logsource:
  product: windows
  service: security
  definition: 'Requirements: The advanced audit policy setting "Object Access > Audit File Share" must be configured for Success/Failure'
detection:
  selection:
    EventID: 5140
    ShareName: Admin$
  filter_main_computer_account:
    SubjectUserName|endswith: $
  condition: selection and not 1 of filter_*
falsepositives:
  - Legitimate administrative activity
level: low
license: DRL-1.1
related:
  - id: 098d7118-55bc-4912-a836-dc6483a8d150
    type: derived

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