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Detection rules › Sigma

Import PowerShell Modules From Suspicious Directories - ProcCreation

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

Detects powershell scripts that import modules from suspicious directories

MITRE ATT&CK coverage

TacticTechniques
ExecutionT1059.001 Command and Scripting Interpreter: PowerShell

Event coverage

ProviderEventTitle
SysmonEvent ID 1Process creation
Security-AuditingEvent ID 4688A new process has been created.

Rule body yaml

title: Import PowerShell Modules From Suspicious Directories - ProcCreation
id: c31364f7-8be6-4b77-8483-dd2b5a7b69a3
related:
    - id: 21f9162c-5f5d-4b01-89a8-b705bd7d10ab
      type: similar
status: test
description: Detects powershell scripts that import modules from suspicious directories
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1003.002/T1003.002.md
author: Nasreddine Bencherchali (Nextron Systems)
date: 2023-01-10
tags:
    - attack.execution
    - attack.t1059.001
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        CommandLine|contains:
            - 'Import-Module "$Env:Temp\'
            - Import-Module '$Env:Temp\
            - 'Import-Module $Env:Temp\'
            - 'Import-Module "$Env:Appdata\'
            - Import-Module '$Env:Appdata\
            - 'Import-Module $Env:Appdata\'
            - 'Import-Module C:\Users\Public\'
            # Import-Module alias is "ipmo"
            - 'ipmo "$Env:Temp\'
            - ipmo '$Env:Temp\
            - 'ipmo $Env:Temp\'
            - 'ipmo "$Env:Appdata\'
            - ipmo '$Env:Appdata\
            - 'ipmo $Env:Appdata\'
            - 'ipmo C:\Users\Public\'
    condition: selection
falsepositives:
    - Unknown
level: medium

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    CommandLine|contains:
        - 'Import-Module "$Env:Temp\'
        - Import-Module '$Env:Temp\
        - 'Import-Module $Env:Temp\'
        - 'Import-Module "$Env:Appdata\'
        - Import-Module '$Env:Appdata\
        - 'Import-Module $Env:Appdata\'
        - 'Import-Module C:\Users\Public\'
        - 'ipmo "$Env:Temp\'
        - ipmo '$Env:Temp\
        - 'ipmo $Env:Temp\'
        - 'ipmo "$Env:Appdata\'
        - ipmo '$Env:Appdata\
        - 'ipmo $Env:Appdata\'
        - 'ipmo C:\Users\Public\'

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
CommandLinematch
  • Import-Module "$Env:Appdata\
  • Import-Module "$Env:Temp\
  • Import-Module $Env:Appdata\
  • Import-Module $Env:Temp\
  • Import-Module '$Env:Appdata\
  • Import-Module '$Env:Temp\
  • Import-Module C:\Users\Public\
  • ipmo "$Env:Appdata\
  • ipmo "$Env:Temp\
  • ipmo $Env:Appdata\
  • ipmo $Env:Temp\
  • ipmo '$Env:Appdata\
  • ipmo '$Env:Temp\
  • ipmo C:\Users\Public\