Potentially Suspicious Rundll32.EXE Execution of UDL File

Detects the execution of rundll32.exe with the oledb32.dll library to open a UDL file. Threat actors can abuse this technique as a phishing vector to capture authentication credentials or other sensitive data.

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Detection logic

selection_parent

ParentImage|endswith: \explorer.exe

selection_img

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

selection_cli

CommandLine|contains|all:
  - oledb32.dll
  - ",OpenDSLFile "
  - \\Users\\*\\Downloads\\
CommandLine|endswith: .udl

Condition

all of selection_*

Raw YAML

title: Potentially Suspicious Rundll32.EXE Execution of UDL File
id: 0ea52357-cd59-4340-9981-c46c7e900428
status: test
description: |
    Detects the execution of rundll32.exe with the oledb32.dll library to open a UDL file.
    Threat actors can abuse this technique as a phishing vector to capture authentication credentials or other sensitive data.
references:
    - https://trustedsec.com/blog/oops-i-udld-it-again
author: '@kostastsale'
date: 2024-08-16
tags:
    - attack.execution
    - attack.command-and-control
    - attack.stealth
    - attack.t1218.011
    - attack.t1071
logsource:
    category: process_creation
    product: windows
detection:
    selection_parent:
        ParentImage|endswith: '\explorer.exe'
    selection_img:
        - Image|endswith: '\rundll32.exe'
        - OriginalFileName: 'RUNDLL32.EXE'
    selection_cli:
        CommandLine|contains|all:
            - 'oledb32.dll'
            - ',OpenDSLFile '
            - '\\Users\\*\\Downloads\\' # Note: You can adjust the path to the download directory or other directories according to your environment.
        CommandLine|endswith: '.udl'
    condition: all of selection_*
falsepositives:
    - UDL files serve as a convenient and flexible tool for managing and testing database connections in various development and administrative scenarios.
level: medium