title: Suspicious Csc.exe Source File Folder
id: dcaa3f04-70c3-427a-80b4-b870d73c94c4
description: Detects a suspicious execution of csc.exe, which uses a source in a suspicious folder (e.g. AppData)
status: experimental
references:
    - https://securityboulevard.com/2019/08/agent-tesla-evading-edr-by-removing-api-hooks/
    - https://www.clearskysec.com/wp-content/uploads/2018/11/MuddyWater-Operations-in-Lebanon-and-Oman.pdf
    - https://app.any.run/tasks/c6993447-d1d8-414e-b856-675325e5aa09/
    - https://twitter.com/gN3mes1s/status/1206874118282448897
author: Florian Roth
date: 2019/08/24
modified: 2021/02/01
tags:
    - attack.defense_evasion
    - attack.t1500 # an old one
    - attack.t1027.004
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith: '\csc.exe'
        CommandLine|contains:
            - '\AppData\'
            - '\Windows\Temp\'
    filter:
        - ParentImage|startswith: 'C:\Program Files'  # https://twitter.com/gN3mes1s/status/1206874118282448897
        - ParentImage|endswith:
            - '\sdiagnhost.exe'  # https://twitter.com/gN3mes1s/status/1206874118282448897
            - '\w3wp.exe'        # https://twitter.com/gabriele_pippi/status/1206907900268072962
        - ParentCommandLine|contains:
            - '\ProgramData\Microsoft\Windows Defender Advanced Threat Protection'
    condition: selection and not filter
falsepositives:
    - https://twitter.com/gN3mes1s/status/1206874118282448897
    - https://twitter.com/gabriele_pippi/status/1206907900268072962
level: high