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Detection rules › Sigma

Suspicious Provlaunch.EXE Child Process

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

Detects suspicious child processes of "provlaunch.exe" which might indicate potential abuse to proxy execution.

MITRE ATT&CK coverage

TacticTechniques
Stealth

Telemetry coverage

ProviderRecord / event type
SysmonEvent ID 1: Process creation
Security-AuditingEvent ID 4688: A new process has been created.

Rule body

title: Suspicious Provlaunch.EXE Child Process
id: f9999590-1f94-4a34-a91e-951e47bedefd
related:
    - id: 7f5d1c9a-3e83-48df-95a7-2b98aae6c13c # CLI Generic
      type: similar
    - id: 2a4b3e61-9d22-4e4a-b60f-6e8f0cde6f25 # CLI Registry
      type: similar
    - id: 7021255e-5db3-4946-a8b9-0ba7a4644a69 # Registry
      type: similar
status: test
description: Detects suspicious child processes of "provlaunch.exe" which might indicate potential abuse to proxy execution.
references:
    - https://lolbas-project.github.io/lolbas/Binaries/Provlaunch/
    - https://twitter.com/0gtweet/status/1674399582162153472
author: Nasreddine Bencherchali (Nextron Systems)
date: 2023-08-08
tags:
    - attack.stealth
    - attack.t1218
logsource:
    category: process_creation
    product: windows
detection:
    selection_parent:
        ParentImage|endswith: '\provlaunch.exe'
    selection_child:
        - Image|endswith:
              - '\calc.exe'
              - '\cmd.exe'
              - '\cscript.exe'
              - '\mshta.exe'
              - '\notepad.exe'
              - '\powershell.exe'
              - '\pwsh.exe'
              - '\regsvr32.exe'
              - '\rundll32.exe'
              - '\wscript.exe'
        - Image|contains:
              - ':\PerfLogs\'
              - ':\Temp\'
              - ':\Users\Public\'
              - '\AppData\Temp\'
              - '\Windows\System32\Tasks\'
              - '\Windows\Tasks\'
              - '\Windows\Temp\'
    condition: all of selection_*
falsepositives:
    - Unknown
level: high

Stages and Predicates

Stage 0: condition

all of selection_*

Stage 1: selection_parent

selection_parent:
    ParentImage|endswith: '\provlaunch.exe'

Stage 2: selection_child

selection_child:
    - Image|endswith:
          - '\calc.exe'
          - '\cmd.exe'
          - '\cscript.exe'
          - '\mshta.exe'
          - '\notepad.exe'
          - '\powershell.exe'
          - '\pwsh.exe'
          - '\regsvr32.exe'
          - '\rundll32.exe'
          - '\wscript.exe'
    - Image|contains:
          - ':\PerfLogs\'
          - ':\Temp\'
          - ':\Users\Public\'
          - '\AppData\Temp\'
          - '\Windows\System32\Tasks\'
          - '\Windows\Tasks\'
          - '\Windows\Temp\'

Indicators

These rows show field, operator, and value matches.

FieldKindValuesSearch
Imageends_with
  • \calc.exe corpus 14 (sigma 14)
  • \cmd.exe corpus 130 (sigma 130)
  • \cscript.exe corpus 72 (sigma 72)
  • \mshta.exe corpus 66 (sigma 66)
  • \notepad.exe corpus 10 (sigma 10)
  • \powershell.exe corpus 179 (sigma 178, kusto 1)
  • \pwsh.exe corpus 165 (sigma 164, kusto 1)
  • \regsvr32.exe corpus 64 (sigma 64)
  • \rundll32.exe corpus 94 (sigma 94)
  • \wscript.exe corpus 74 (sigma 74)
field:"Image" kind:ends_with
Imagematch
  • :\PerfLogs\ corpus 9 (sigma 9)
  • :\Temp\ corpus 11 (sigma 11)
  • :\Users\Public\ corpus 13 (sigma 13)
  • \AppData\Temp\ corpus 2 (sigma 2)
  • \Windows\System32\Tasks\ corpus 3 (sigma 3)
  • \Windows\Tasks\ corpus 3 (sigma 3)
  • \Windows\Temp\ corpus 7 (sigma 7)
field:"Image" kind:match
ParentImageends_with
  • \provlaunch.exe corpus 2 (sigma 2)
field:"ParentImage" kind:ends_with value:"\provlaunch.exe"