PowerShell Download Pattern

Status: test
Severity: medium
Log source: category process_creation, product windows
Author: Florian Roth (Nextron Systems), oscd.community, Jonhnathan Ribeiro
Source: github.com/SigmaHQ/sigma

Detects a Powershell process that contains download commands in its command line string

MITRE ATT&CK coverage

Tactic	Techniques
Execution	`T1059.001` Command and Scripting Interpreter: PowerShell

Telemetry coverage

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

Rule body

title: PowerShell Download Pattern
id: 3b6ab547-8ec2-4991-b9d2-2b06702a48d7
related:
    - id: e6c54d94-498c-4562-a37c-b469d8e9a275
      type: derived
    - id: 8f70ac5f-1f6f-4f8e-b454-db19561216c5
      type: obsolete
status: test
description: Detects a Powershell process that contains download commands in its command line string
references:
    - https://blog.redteam.pl/2020/06/black-kingdom-ransomware.html
    - https://lab52.io/blog/winter-vivern-all-summer/
    - https://hatching.io/blog/powershell-analysis/
author: Florian Roth (Nextron Systems), oscd.community, Jonhnathan Ribeiro
date: 2019-01-16
modified: 2025-10-20
tags:
    - attack.execution
    - attack.t1059.001
logsource:
    category: process_creation
    product: windows
detection:
    selection_img:
        - Image|endswith:
              - '\powershell_ise.exe'
              - '\powershell.exe'
              - '\pwsh.exe'
        - OriginalFileName:
              - 'PowerShell_ISE.EXE'
              - 'PowerShell.EXE'
              - 'pwsh.dll'
    selection_cli:
        CommandLine|contains|all:
            - 'new-object'
            - 'net.webclient).'
            - 'download'
        CommandLine|contains:
            - 'string('
            - 'file('
    condition: all of selection_*
falsepositives:
    - Unknown
level: medium

Stages and Predicates

Stage 0: `condition`

all of selection_*

Stage 1: `selection_img`

selection_img:
    - Image|endswith:
          - '\powershell_ise.exe'
          - '\powershell.exe'
          - '\pwsh.exe'
    - OriginalFileName:
          - 'PowerShell_ISE.EXE'
          - 'PowerShell.EXE'
          - 'pwsh.dll'

Stage 2: `selection_cli`

selection_cli:
    CommandLine|contains|all:
        - 'new-object'
        - 'net.webclient).'
        - 'download'
    CommandLine|contains:
        - 'string('
        - 'file('

Indicators

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`CommandLine`	match	`download` corpus 4 (elastic 3, sigma 1) `file(` `net.webclient).` `new-object` corpus 3 (sigma 3) `string(`	`field:"CommandLine" kind:match`
`Image`	ends_with	`\powershell.exe` corpus 179 (sigma 178, kusto 1) `\powershell_ise.exe` corpus 41 (sigma 41) `\pwsh.exe` corpus 165 (sigma 164, kusto 1)	`field:"Image" kind:ends_with`
`OriginalFileName`	eq	`PowerShell.EXE` corpus 138 (sigma 84, splunk 30, elastic 24) `PowerShell_ISE.EXE` corpus 51 (splunk 30, sigma 18, elastic 3) `pwsh.dll` corpus 112 (sigma 79, splunk 30, elastic 3)	`field:"OriginalFileName" kind:eq`

PowerShell Download Pattern

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`