Detection rules › Sigma

Access To ADMIN$ Network Share

Status
test
Severity
low
Log source
product windows, service security
Author
Florian Roth (Nextron Systems)
Source
github.com/SigmaHQ/sigma

Detects access to ADMIN$ network share

Known false positives

  • Legitimate administrative activity

MITRE ATT&CK coverage

Telemetry coverage

Rule body

title: Access To ADMIN$ Network Share
id: 098d7118-55bc-4912-a836-dc6483a8d150
status: test
description: Detects access to ADMIN$ network share
references:
    - https://learn.microsoft.com/en-us/previous-versions/windows/it-pro/windows-10/security/threat-protection/auditing/event-5140
author: Florian Roth (Nextron Systems)
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

Stages and Predicates

Stage 0: condition

selection and not 1 of filter_*

Stage 1: selection

selection:
    EventID: 5140
    ShareName: 'Admin$'

Stage 2: not filter_main_computer_account

filter_main_computer_account:
    SubjectUserName|endswith: '$'

Exclusions

The rule actively suppresses these predicates.

FieldKindExcluded valuesSearch
SubjectUserNameends_with$excludes:SubjectUserName field:"SubjectUserName" value:"$"

Indicators

These rows show field, operator, and value matches.