Detection rules › Sigma

Nslookup PowerShell Download Cradle - ProcessCreation

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

Detects suspicious powershell download cradle using nslookup. This cradle uses nslookup to extract payloads from DNS records

MITRE ATT&CK coverage

TacticTechniques
StealthNo specific technique

Telemetry coverage

ProviderRecord / event type
SysmonEvent ID 1: Process creation

Rule body

title: Nslookup PowerShell Download Cradle - ProcessCreation
id: 1b3b01c7-84e9-4072-86e5-fc285a41ff23
related:
    - id: 72671447-4352-4413-bb91-b85569687135
      type: obsolete
    - id: 999bff6d-dc15-44c9-9f5c-e1051bfc86e1
      type: similar
status: test
description: Detects suspicious powershell download cradle using nslookup. This cradle uses nslookup to extract payloads from DNS records
references:
    - https://twitter.com/Alh4zr3d/status/1566489367232651264
author: Nasreddine Bencherchali (Nextron Systems)
date: 2022-09-05
modified: 2022-12-19
tags:
    - attack.stealth
logsource:
    category: process_creation
    product: windows
detection:
    selection_img:
        - Image|contains: '\nslookup.exe'
        - OriginalFileName: '\nslookup.exe'
    selection_cmd:
        ParentImage|endswith:
            - '\powershell.exe'
            - '\pwsh.exe'
        CommandLine|contains:
            - ' -q=txt '
            - ' -querytype=txt '
    condition: all of selection_*
falsepositives:
    - Unknown
level: medium

Stages and Predicates

Stage 0: condition

all of selection_*

Stage 1: selection_img

selection_img:
    - Image|contains: '\nslookup.exe'
    - OriginalFileName: '\nslookup.exe'

Stage 2: selection_cmd

selection_cmd:
    ParentImage|endswith:
        - '\powershell.exe'
        - '\pwsh.exe'
    CommandLine|contains:
        - ' -q=txt '
        - ' -querytype=txt '

Indicators

These rows show field, operator, and value matches.

FieldKindValuesSearch
CommandLinematch
  • -q=txt
  • -querytype=txt
field:"CommandLine" kind:match
Imagematch
  • \nslookup.exe
field:"Image" kind:match value:"\nslookup.exe"
OriginalFileNameeq
  • \nslookup.exe
field:"OriginalFileName" kind:eq value:"\nslookup.exe"
ParentImageends_with
  • \powershell.exe corpus 24 (sigma 24)
  • \pwsh.exe corpus 21 (sigma 21)
field:"ParentImage" kind:ends_with