sigmamediumHunting

Potential DLL Sideloading Of MsCorSvc.DLL

Detects potential DLL sideloading of "mscorsvc.dll".

MITRE ATT&CK

privilege-escalationpersistencedefense-evasion

Detection Query

selection:
  ImageLoaded|endswith: \mscorsvc.dll
filter_main_generic:
  ImageLoaded|startswith:
    - C:\Windows\Microsoft.NET\Framework\
    - C:\Windows\Microsoft.NET\Framework64\
    - C:\Windows\Microsoft.NET\FrameworkArm\
    - C:\Windows\Microsoft.NET\FrameworkArm64\
    - C:\Windows\WinSxS\
condition: selection and not 1 of filter_main_*

Author

Wietze Beukema

Created

2024-07-11

Data Sources

windowsImage Load Events

Platforms

windows

References

https://hijacklibs.net/entries/microsoft/built-in/mscorsvc.html

Tags

attack.privilege-escalationattack.persistenceattack.defense-evasionattack.t1574.001

Raw Content

title: Potential DLL Sideloading Of MsCorSvc.DLL
id: cdb15e19-c2d0-432a-928e-e49c8c60dcf2
status: test
description: Detects potential DLL sideloading of "mscorsvc.dll".
references:
    - https://hijacklibs.net/entries/microsoft/built-in/mscorsvc.html
author: Wietze Beukema
date: 2024-07-11
modified: 2025-02-26
tags:
    - attack.privilege-escalation
    - attack.persistence
    - attack.defense-evasion
    - attack.t1574.001
logsource:
    product: windows
    category: image_load
detection:
    selection:
        ImageLoaded|endswith: '\mscorsvc.dll'
    filter_main_generic:
        ImageLoaded|startswith:
            - 'C:\Windows\Microsoft.NET\Framework\'
            - 'C:\Windows\Microsoft.NET\Framework64\'
            - 'C:\Windows\Microsoft.NET\FrameworkArm\'
            - 'C:\Windows\Microsoft.NET\FrameworkArm64\'
            - 'C:\Windows\WinSxS\'
    condition: selection and not 1 of filter_main_*
falsepositives:
    - Legitimate applications loading their own versions of the DLL mentioned in this rule.
level: medium