sigmahighHunting

Potential Renamed Rundll32 Execution

Detects when 'DllRegisterServer' is called in the commandline and the image is not rundll32. This could mean that the 'rundll32' utility has been renamed in order to avoid detection

Detection Query

selection:
  CommandLine|contains: DllRegisterServer
filter:
  Image|endswith: \rundll32.exe
condition: selection and not filter

Author

Nasreddine Bencherchali (Nextron Systems)

Created

2022-08-22

Data Sources

windowsProcess Creation Events

Platforms

windows

References

Tags

attack.execution

Raw Content

title: Potential Renamed Rundll32 Execution
id: 2569ed8c-1147-498a-9b8c-2ad3656b10ed
related:
    - id: 0ba1da6d-b6ce-4366-828c-18826c9de23e
      type: derived
status: test
description: Detects when 'DllRegisterServer' is called in the commandline and the image is not rundll32. This could mean that the 'rundll32' utility has been renamed in order to avoid detection
references:
    - https://twitter.com/swisscom_csirt/status/1331634525722521602?s=20
    - https://app.any.run/tasks/f74c5157-8508-4ac6-9805-d63fe7b0d399/
author: Nasreddine Bencherchali (Nextron Systems)
date: 2022-08-22
modified: 2023-02-03
tags:
    - attack.execution
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        CommandLine|contains: 'DllRegisterServer'
    filter:
        Image|endswith: '\rundll32.exe'
    condition: selection and not filter
falsepositives:
    - Unlikely
level: high