Suspicious Assembly DLL Creation Through AspNetCompiler (via file_event)

title: Suspicious Assembly DLL Creation Through AspNetCompiler (via file_event)
id: 709d9601-9fad-54cd-adb6-09a5a8fd864b
status: stable
description: This rule detects the creation of new DLL assembly files by "aspnet_compiler.exe", which could be a sign of "aspnet_compiler" misuse to proxy execution through a build provider.
references:
    - Internal Research
author: Huntrule Team
date: 2026-05-05
tags:
    - attack.execution
    - attack.defense-evasion
    - attack.t1127
logsource:
    product: windows
    category: file_event
detection:
    selection:
        Image|endswith: '\aspnet_compiler.exe'
        TargetFilename|contains|all:
            - '\Temporary ASP.NET Files\'
            - '\assembly\tmp\'
            - '.dll'
    condition: selection
falsepositives:
    - Unknown
level: medium