Suspicious Binary Writes Via AnyDesk

title: Suspicious Binary Writes Via AnyDesk
id: 2d367498-5112-4ae5-a06a-96e7bc33a211
status: test
description: |
    Detects AnyDesk writing binary files to disk other than "gcapi.dll".
    According to RedCanary research it is highly abnormal for AnyDesk to write executable files to disk besides gcapi.dll,
    which is a legitimate DLL that is part of the Google Chrome web browser used to interact with the Google Cloud API. (See reference section for more details)
references:
    - https://redcanary.com/blog/misbehaving-rats/
    - https://thedfirreport.com/2025/02/24/confluence-exploit-leads-to-lockbit-ransomware/
author: Nasreddine Bencherchali (Nextron Systems)
date: 2022-09-28
modified: 2025-02-24
tags:
    - attack.command-and-control
    - attack.t1219.002
logsource:
    product: windows
    category: file_event
detection:
    selection:
        Image|endswith:
            - '\AnyDesk.exe'
            - '\AnyDeskMSI.exe'
        TargetFilename|endswith:
            - '.dll'
            - '.exe'
    filter_dlls:
        TargetFilename|endswith: '\gcapi.dll'
    condition: selection and not 1 of filter_*
falsepositives:
    - Unknown
level: high