Analysis

  • max time kernel
    898s
  • max time network
    899s
  • platform
    windows10-ltsc_2021_x64
  • resource
    win10ltsc2021-20260911-en
  • resource tags

    arch:x64arch:x86image:win10ltsc2021-20260911-enlocale:en-usos:windows10-ltsc_2021-x64systemwindows
  • submitted
    16/09/2026, 22:39

General

  • Target
    MasonClient.exe
  • Size 49KB
  • Sample260916-2k66jsfb63
  • SHA256 3fd1677145bc6e50d8b9d26d5369360e84c9063edcf8aae7972ee029fd0d5e83
  • MD5 SHA1 SHA512 SSDEEP TLSH

Malware Config

Extracted

Family
  • neptunerat

C2
  • 188.209.211.120:8080

Attributes
  • filename

    USB.exe

  • group

    MasonGroup

  • key

    dzLRNpkgEBxWJ2Jm

  • rat_name

    MasonRAT

Signatures

  • Family: NeptuneRAT, MasonRAT

    NeptuneRAT aka MasonRAT is a trojan written in C#.

  • Detects NeptuneRAT stealer 2 IoCs
  • Checks computer location settings 2 TTPs 1 IoCs

    Looks up country code configured in the registry, likely geofence.

  • Executes dropped EXE 16 IoCs
  • Adds Run key to start application 2 TTPs 1 IoCs
  • Enumerates physical storage devices 1 TTPs

    Attempts to interact with connected storage/optical drive(s).

  • Scheduled Task/Job: Scheduled Task 1 TTPs 1 IoCs

    Schtasks is often used by malware for persistence or to perform post-infection execution.

  • Suspicious use of AdjustPrivilegeToken 17 IoCs
  • Suspicious use of WriteProcessMemory 1 IoCs
  • Uses Task Scheduler COM API 1 TTPs

    The Task Scheduler COM API can be used to schedule applications to run on boot or at set times.

Processes

  • C:\Users\Admin\AppData\Local\Temp\MasonClient.exe
    "C:\Users\Admin\AppData\Local\Temp\MasonClient.exe"
    1⤵
    • Checks computer location settings
    • Adds Run key to start application
    • Suspicious use of AdjustPrivilegeToken
    • Suspicious use of WriteProcessMemory
    PID:892
    • C:\Windows\System32\schtasks.exe
      "C:\Windows\System32\schtasks.exe" /create /f /sc minute /mo 1 /tn "MasonClient" /tr "C:\Users\Admin\AppData\Roaming\MasonClient.exe"
      2⤵
      • Scheduled Task/Job: Scheduled Task
      PID:4652
  • C:\Users\Admin\AppData\Roaming\MasonClient.exe
    C:\Users\Admin\AppData\Roaming\MasonClient.exe
    1⤵
    • Executes dropped EXE
    • Suspicious use of AdjustPrivilegeToken
    PID:5004
  • C:\Users\Admin\AppData\Roaming\MasonClient.exe
    "C:\Users\Admin\AppData\Roaming\MasonClient.exe"
    1⤵
    • Executes dropped EXE
    • Suspicious use of AdjustPrivilegeToken
    PID:5652
  • C:\Users\Admin\AppData\Roaming\MasonClient.exe
    "C:\Users\Admin\AppData\Roaming\MasonClient.exe"
    1⤵
    • Executes dropped EXE
    • Suspicious use of AdjustPrivilegeToken
    PID:2844
  • C:\Users\Admin\AppData\Roaming\MasonClient.exe
    "C:\Users\Admin\AppData\Roaming\MasonClient.exe"
    1⤵
    • Executes dropped EXE
    • Suspicious use of AdjustPrivilegeToken
    PID:6008
  • C:\Users\Admin\AppData\Roaming\MasonClient.exe
    "C:\Users\Admin\AppData\Roaming\MasonClient.exe"
    1⤵
    • Executes dropped EXE
    • Suspicious use of AdjustPrivilegeToken
    PID:5128
  • C:\Users\Admin\AppData\Roaming\MasonClient.exe
    "C:\Users\Admin\AppData\Roaming\MasonClient.exe"
    1⤵
    • Executes dropped EXE
    • Suspicious use of AdjustPrivilegeToken
    PID:5864
  • C:\Users\Admin\AppData\Roaming\MasonClient.exe
    "C:\Users\Admin\AppData\Roaming\MasonClient.exe"
    1⤵
    • Executes dropped EXE
    • Suspicious use of AdjustPrivilegeToken
    PID:5108
  • C:\Users\Admin\AppData\Roaming\MasonClient.exe
    "C:\Users\Admin\AppData\Roaming\MasonClient.exe"
    1⤵
    • Executes dropped EXE
    • Suspicious use of AdjustPrivilegeToken
    PID:5600
  • C:\Users\Admin\AppData\Roaming\MasonClient.exe
    "C:\Users\Admin\AppData\Roaming\MasonClient.exe"
    1⤵
    • Executes dropped EXE
    • Suspicious use of AdjustPrivilegeToken
    PID:5812
  • C:\Users\Admin\AppData\Roaming\MasonClient.exe
    "C:\Users\Admin\AppData\Roaming\MasonClient.exe"
    1⤵
    • Executes dropped EXE
    • Suspicious use of AdjustPrivilegeToken
    PID:4672
  • C:\Users\Admin\AppData\Roaming\MasonClient.exe
    "C:\Users\Admin\AppData\Roaming\MasonClient.exe"
    1⤵
    • Executes dropped EXE
    • Suspicious use of AdjustPrivilegeToken
    PID:5968
  • C:\Users\Admin\AppData\Roaming\MasonClient.exe
    "C:\Users\Admin\AppData\Roaming\MasonClient.exe"
    1⤵
    • Executes dropped EXE
    • Suspicious use of AdjustPrivilegeToken
    PID:1276
  • C:\Users\Admin\AppData\Roaming\MasonClient.exe
    "C:\Users\Admin\AppData\Roaming\MasonClient.exe"
    1⤵
    • Executes dropped EXE
    • Suspicious use of AdjustPrivilegeToken
    PID:804
  • C:\Users\Admin\AppData\Roaming\MasonClient.exe
    "C:\Users\Admin\AppData\Roaming\MasonClient.exe"
    1⤵
    • Executes dropped EXE
    • Suspicious use of AdjustPrivilegeToken
    PID:3472
  • C:\Users\Admin\AppData\Roaming\MasonClient.exe
    "C:\Users\Admin\AppData\Roaming\MasonClient.exe"
    1⤵
    • Executes dropped EXE
    • Suspicious use of AdjustPrivilegeToken
    PID:5760
  • C:\Users\Admin\AppData\Roaming\MasonClient.exe
    "C:\Users\Admin\AppData\Roaming\MasonClient.exe"
    1⤵
    • Executes dropped EXE
    • Suspicious use of AdjustPrivilegeToken
    PID:1296

Network

        MITRE ATT&CK Enterprise v16

        Replay Monitor

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        Downloads

        MasonClient.exe.log

        • Path C:\Users\Admin\AppData\Local\Microsoft\CLR_v4.0\UsageLogs\MasonClient.exe.log
        • Size 654B
        • SHA256 d39a78fabca39532fcb85ce908781a75132e1bd01cc50a3b290dd87127837d63
        • MD5 SHA1 SHA512 TLSH

        MasonClient.exe

        • Path C:\Users\Admin\AppData\Roaming\MasonClient.exe
        • Size 49KB
        • SHA256 3fd1677145bc6e50d8b9d26d5369360e84c9063edcf8aae7972ee029fd0d5e83
        • MD5 SHA1 SHA512 SSDEEP TLSH

        memory/892-0-0x0000000000F10000-0x0000000000F22000-memory.dmp

        memory/892-1-0x000000001BD90000-0x000000001BDA0000-memory.dmp

        memory/892-4-0x000000001BD90000-0x000000001BDA0000-memory.dmp