Potential DLL Sideloading Using Coregen.exe — Sigma Rule

Rule metadata and linked tags

Author: frack113. Source status: test; severity: medium. Source dates: 2022-12-31 / not supplied.

{
  "category": "image_load",
  "product": "windows"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: bdde986f2f8f60be08a75432ad744602e4c3de147937085f16d8c802fef9c9ec

Detection logic

Original source YAML. Source-tag agreement is not proof of complete semantic coverage. This rule has not been compiled for a SIEM backend or validated against live telemetry here.

title: Potential DLL Sideloading Using Coregen.exe
id: 0fa66f66-e3f6-4a9c-93f8-4f2610b00171
status: test
description: Detect usage of the "coregen.exe" (Microsoft CoreCLR Native Image Generator) binary to sideload arbitrary DLLs.
references:
    - https://lolbas-project.github.io/lolbas/OtherMSBinaries/Coregen/
author: frack113
date: 2022-12-31
tags:
    - attack.privilege-escalation
    - attack.stealth
    - attack.t1218
    - attack.t1055
logsource:
    category: image_load
    product: windows
detection:
    selection:
        Image|endswith: '\coregen.exe'
    filter_main_legit_paths:
        ImageLoaded|startswith:
            - 'C:\Program Files (x86)\Microsoft Silverlight\'
            - 'C:\Program Files\Microsoft Silverlight\'
            - 'C:\Windows\System32\'
            - 'C:\Windows\SysWOW64\'
    condition: selection and not 1 of filter_main_*
falsepositives:
    - Unknown
level: medium

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://lolbas-project.github.io/lolbas/OtherMSBinaries/Coregen/