Windows Share Mount Via Net.EXE

Status: test
Severity: low
Log source: category process_creation, product windows
Author: Nasreddine Bencherchali (Nextron Systems)
Source: github.com/SigmaHQ/sigma

Detects when a share is mounted using the "net.exe" utility

Known false positives

Legitimate activity by administrators and scripts

MITRE ATT&CK coverage

Tactic	Techniques
Lateral Movement	`T1021.002` Remote Services: SMB/Windows Admin Shares

Telemetry coverage

Provider	Record / event type
Sysmon	Event ID 1: Process creation

Rule body

title: Windows Share Mount Via Net.EXE
id: f117933c-980c-4f78-b384-e3d838111165
related:
    - id: 3abd6094-7027-475f-9630-8ab9be7b9725
      type: similar
status: test
description: Detects when a share is mounted using the "net.exe" utility
references:
    - https://drive.google.com/file/d/1lKya3_mLnR3UQuCoiYruO3qgu052_iS_/view
author: Nasreddine Bencherchali (Nextron Systems)
date: 2023-02-02
modified: 2023-02-21
tags:
    - attack.lateral-movement
    - attack.t1021.002
logsource:
    category: process_creation
    product: windows
detection:
    selection_img:
        - Image|endswith:
              - '\net.exe'
              - '\net1.exe'
        - OriginalFileName:
              - 'net.exe'
              - 'net1.exe'
    selection_cli:
        CommandLine|contains:
            - ' use '
            - ' \\\\'
    condition: all of selection_*
falsepositives:
    - Legitimate activity by administrators and scripts
level: low

Stages and Predicates

Stage 0: `condition`

all of selection_*

Stage 1: `selection_img`

selection_img:
    - Image|endswith:
          - '\net.exe'
          - '\net1.exe'
    - OriginalFileName:
          - 'net.exe'
          - 'net1.exe'

Stage 2: `selection_cli`

selection_cli:
    CommandLine|contains:
        - ' use '
        - ' \\\\'

Indicators

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`CommandLine`	match	`\\\\` corpus 8 (sigma 8) `use` corpus 6 (sigma 6)	`field:"CommandLine" kind:match`
`Image`	ends_with	`\net.exe` corpus 49 (sigma 49) `\net1.exe` corpus 47 (sigma 47)	`field:"Image" kind:ends_with`
`OriginalFileName`	eq	`net.exe` corpus 31 (sigma 19, elastic 10, splunk 2) `net1.exe` corpus 44 (sigma 19, splunk 19, elastic 6)	`field:"OriginalFileName" kind:eq`

Windows Share Mount Via Net.EXE

Known false positives

MITRE ATT&CK coverage

Telemetry coverage

Rule body

Stages and Predicates

Stage 0: condition

Stage 1: selection_img

Stage 2: selection_cli

Indicators

Stage 0: `condition`

Stage 1: `selection_img`

Stage 2: `selection_cli`