Detection rules › Sigma

Potential ShellDispatch.DLL Functionality Abuse

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

Detects potential "ShellDispatch.dll" functionality abuse to execute arbitrary binaries via "ShellExecute"

Known false positives

  • Unlikely

MITRE ATT&CK coverage

TacticTechniques
ExecutionNo specific technique
StealthNo specific technique

Telemetry coverage

ProviderRecord / event type
SysmonEvent ID 1: Process creation

Rule body

title: Potential ShellDispatch.DLL Functionality Abuse
id: 82343930-652f-43f5-ab70-2ee9fdd6d5e9
status: test
description: Detects potential "ShellDispatch.dll" functionality abuse to execute arbitrary binaries via "ShellExecute"
references:
    - https://www.hexacorn.com/blog/2023/06/07/this-lolbin-doesnt-exist/
author: X__Junior (Nextron Systems)
date: 2023-06-20
tags:
    - attack.execution
    - attack.stealth
logsource:
    category: process_creation
    product: windows
detection:
    selection_img:
        - Image|endswith: '\rundll32.exe'
        - OriginalFileName: 'RUNDLL32.EXE'
    selection_cli:
        CommandLine|contains: 'RunDll_ShellExecuteW'
    condition: all of selection_*
falsepositives:
    - Unlikely
level: medium

Stages and Predicates

Stage 0: condition

all of selection_*

Stage 1: selection_img

selection_img:
    - Image|endswith: '\rundll32.exe'
    - OriginalFileName: 'RUNDLL32.EXE'

Stage 2: selection_cli

selection_cli:
    CommandLine|contains: 'RunDll_ShellExecuteW'

Indicators

These rows show field, operator, and value matches.

FieldKindValuesSearch
CommandLinematch
  • RunDll_ShellExecuteW
field:"CommandLine" kind:match value:"RunDll_ShellExecuteW"
Imageends_with
  • \rundll32.exe corpus 94 (sigma 94)
field:"Image" kind:ends_with value:"\rundll32.exe"
OriginalFileNameeq
  • RUNDLL32.EXE corpus 78 (sigma 35, elastic 22, splunk 21)
field:"OriginalFileName" kind:eq value:"RUNDLL32.EXE"