Suspicious Invoke-WebRequest Execution With DirectIP — Sigma Rule

Rule metadata and linked tags

Author: Nasreddine Bencherchali (Nextron Systems). Source status: test; severity: medium. Source dates: 2023-04-21 / not supplied.

{
  "category": "process_creation",
  "product": "windows"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: e5b0e5eb9b046dd6cf20ec1a186d2da54e6129038957c66305ee30ef689d8a57

Detection logic

Original source YAML. Source-tag agreement is not proof of complete semantic coverage. This rule has not been compiled for a SIEM backend or validated against live telemetry here.

title: Suspicious Invoke-WebRequest Execution With DirectIP
id: 1edff897-9146-48d2-9066-52e8d8f80a2f
status: test
description: Detects calls to PowerShell with Invoke-WebRequest cmdlet using direct IP access
references:
    - https://www.huntress.com/blog/critical-vulnerabilities-in-papercut-print-management-software
author: Nasreddine Bencherchali (Nextron Systems)
date: 2023-04-21
tags:
    - attack.command-and-control
    - attack.t1105
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_commands:
        CommandLine|contains:
            # These are all aliases of Invoke-WebRequest
            - 'curl '
            - 'Invoke-RestMethod'
            - 'Invoke-WebRequest'
            - ' irm ' # Space before and after to avoid false positives with 'irm' as a substring
            - 'iwr '
            - 'wget '
    selection_ip:
        # In case of FP with local IPs add additional filters
        CommandLine|contains:
            - '://1'
            - '://2'
            - '://3'
            - '://4'
            - '://5'
            - '://6'
            - '://7'
            - '://8'
            - '://9'
    condition: all of selection_*
falsepositives:
    - Unknown
level: medium

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://www.huntress.com/blog/critical-vulnerabilities-in-papercut-print-management-software