Detection rules › Sigma
Suspicious IO.FileStream
Open a handle on the drive volume via the \.\ DOS device path specifier and perform direct access read of the first few bytes of the volume.
Known false positives
- Legitimate PowerShell scripts
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Stealth |
Telemetry coverage
| Provider | Record / event type |
|---|---|
| PowerShell | Event ID 4104: Creating Scriptblock text (MessageNumber of MessageTotal). |
Rule body
title: Suspicious IO.FileStream
id: 70ad982f-67c8-40e0-a955-b920c2fa05cb
status: test
description: Open a handle on the drive volume via the \\.\ DOS device path specifier and perform direct access read of the first few bytes of the volume.
references:
- https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1006/T1006.md
author: frack113
date: 2022-01-09
modified: 2022-03-05
tags:
- attack.stealth
- attack.t1070.003
logsource:
product: windows
category: ps_script
definition: 'Requirements: Script Block Logging must be enabled'
detection:
selection:
ScriptBlockText|contains|all:
- New-Object
- IO.FileStream
- '\\\\.\\'
condition: selection
falsepositives:
- Legitimate PowerShell scripts
level: medium
Stages and Predicates
Stage 0: condition
selectionStage 1: selection
selection:
ScriptBlockText|contains|all:
- New-Object
- IO.FileStream
- '\\\\.\\'
Indicators
These rows show field, operator, and value matches.
| Field | Kind | Values | Search |
|---|---|---|---|
ScriptBlockText | match |
| field:"ScriptBlockText" kind:match |