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Detection rules › Sigma

Powershell XML Execute Command

Status
test
Severity
medium
Log source
product windows, category ps_script
Author
frack113
Source
github.com/SigmaHQ/sigma

Adversaries may abuse PowerShell commands and scripts for execution. PowerShell is a powerful interactive command-line interface and scripting environment included in the Windows operating system. (Citation: TechNet PowerShell) Adversaries can use PowerShell to perform a number of actions, including discovery of information and execution of code

MITRE ATT&CK coverage

TacticTechniques
ExecutionT1059.001 Command and Scripting Interpreter: PowerShell

Event coverage

ProviderEventTitle
PowerShellEvent ID 4104Creating Scriptblock text (MessageNumber of MessageTotal).

Rule body yaml

title: Powershell XML Execute Command
id: 6c6c6282-7671-4fe9-a0ce-a2dcebdc342b
status: test
description: |
    Adversaries may abuse PowerShell commands and scripts for execution.
    PowerShell is a powerful interactive command-line interface and scripting environment included in the Windows operating system. (Citation: TechNet PowerShell)
    Adversaries can use PowerShell to perform a number of actions, including discovery of information and execution of code
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1059.001/T1059.001.md#atomic-test-8---powershell-xml-requests
author: frack113
date: 2022-01-19
modified: 2023-01-19
tags:
    - attack.execution
    - attack.t1059.001
logsource:
    product: windows
    category: ps_script
    definition: 'Requirements: Script Block Logging must be enabled'
detection:
    selection_xml:
        ScriptBlockText|contains|all:
            - 'New-Object'
            - 'System.Xml.XmlDocument'
            - '.Load'
    selection_exec:
        ScriptBlockText|contains:
            - 'IEX '
            - 'Invoke-Expression '
            - 'Invoke-Command '
            - 'ICM -'
    condition: all of selection_*
falsepositives:
    - Legitimate administrative script
level: medium

Stages and Predicates

Stage 0: condition

all of selection_*

Stage 1: selection_xml

selection_xml:
    ScriptBlockText|contains|all:
        - 'New-Object'
        - 'System.Xml.XmlDocument'
        - '.Load'

Stage 2: selection_exec

selection_exec:
    ScriptBlockText|contains:
        - 'IEX '
        - 'Invoke-Expression '
        - 'Invoke-Command '
        - 'ICM -'

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
ScriptBlockTextmatch
  • .Load
  • ICM -
  • IEX
  • Invoke-Command corpus 2 (sigma 2)
  • Invoke-Expression
  • New-Object corpus 8 (sigma 7, splunk 1)
  • System.Xml.XmlDocument