Third Party Software DLL Sideloading

Hunt Hypothesis

Detects DLL sideloading of DLLs that are part of third party software (zoom, discord…etc)

Detection Rule

Sigma (Original)

title: Third Party Software DLL Sideloading
id: f9df325d-d7bc-4a32-8a1a-2cc61dcefc63
status: test
description: Detects DLL sideloading of DLLs that are part of third party software (zoom, discord....etc)
references:
    - https://hijacklibs.net/ # For list of DLLs that could be sideloaded (search for dlls mentioned here in there)
author: Nasreddine Bencherchali (Nextron Systems), Wietze Beukema (project and research)
date: 2022-08-17
tags:
    - attack.persistence
    - attack.privilege-escalation
    - attack.execution
    - attack.stealth
    - attack.t1574.001
logsource:
    category: image_load
    product: windows
detection:
    # Lenovo
    selection_lenovo:
        ImageLoaded|endswith: '\commfunc.dll'
    filter_lenovo:
        - ImageLoaded|contains: '\AppData\local\Google\Chrome\Application\'
        - ImageLoaded|startswith:
              - 'C:\Program Files\Lenovo\Communications Utility\'
              - 'C:\Program Files (x86)\Lenovo\Communications Utility\'
    # Toshiba
    selection_toshiba:
        ImageLoaded|endswith: '\tosbtkbd.dll'
    filter_toshiba:
        ImageLoaded|startswith:
            - 'C:\Program Files\Toshiba\Bluetooth Toshiba Stack\'
            - 'C:\Program Files (x86)\Toshiba\Bluetooth Toshiba Stack\'
    # Zoom (FP with System32)
    # selection_zoom:
    #     ImageLoaded|endswith: '\version.dll'
    # filter_zoom:
    #     ImageLoaded|startswith: 'C:\Users\'
    #     ImageLoaded|contains: '\AppData\Roaming\Zoom\bin\'
    condition: (selection_lenovo and not filter_lenovo) or (selection_toshiba and not filter_toshiba)
falsepositives:
    - Unknown
level: medium

KQL (Microsoft 365 Defender)

DeviceImageLoadEvents
| where (FolderPath endswith "\\commfunc.dll" and (not((FolderPath contains "\\AppData\\local\\Google\\Chrome\\Application\\" or (FolderPath startswith "C:\\Program Files\\Lenovo\\Communications Utility\\" or FolderPath startswith "C:\\Program Files (x86)\\Lenovo\\Communications Utility\\"))))) or (FolderPath endswith "\\tosbtkbd.dll" and (not((FolderPath startswith "C:\\Program Files\\Toshiba\\Bluetooth Toshiba Stack\\" or FolderPath startswith "C:\\Program Files (x86)\\Toshiba\\Bluetooth Toshiba Stack\\"))))

Required Data Sources

False Positive Guidance

• Unknown

MITRE ATT&CK Context

• Tactic: Persistence
• Tactic: Privilege Escalation
• Tactic: Execution
• Technique: T1574.001 — T1574.001

References

• https://hijacklibs.net/
• SigmaHQ Rule