Analysis

  • max time kernel
    149s
  • max time network
    125s
  • platform
    windows11-ltsc_2024_x64
  • resource
    win11ltsc2024-20260911-en
  • resource tags

    arch:x64arch:x86image:win11ltsc2024-20260911-enlocale:en-usos:windows11-ltsc_2024-x64systemwindows
  • submitted
    27/09/2026, 04:49

General

  • Target
    MasonClient.exe
  • Size 49KB
  • Sample260927-ffysqa1thw
  • SHA256 64f36ad264c04537c28687e5ee00ae3dbd3462e126cfee473f87344417f88b00
  • MD5 SHA1 SHA512 SSDEEP TLSH

Malware Config

Extracted

Family
  • neptunerat

C2
  • 51891.portmap.host:51891

Attributes
  • filename

    USB.exe

  • group

    MasonGroup

  • key

    EpQDg3OpZvXJqPKh

  • rat_name

    MasonRAT

Signatures

  • Family: NeptuneRAT, MasonRAT

    NeptuneRAT aka MasonRAT is a trojan written in C#.

  • Detects NeptuneRAT stealer 2 IoCs
  • Executes dropped EXE 4 IoCs
  • Enumerates physical storage devices 1 TTPs

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

  • Reads the TCP/IP host and domain name from the registry 1 TTPs 2 IoCs

    The configured hostname and DNS domain identify the machine and are commonly collected to profile a host before it reports in.

  • 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 5 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⤵
    • Reads the TCP/IP host and domain name from the registry
    • Suspicious use of AdjustPrivilegeToken
    • Suspicious use of WriteProcessMemory
    PID:5840
    • 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:4388
  • C:\Users\Admin\AppData\Roaming\MasonClient.exe
    C:\Users\Admin\AppData\Roaming\MasonClient.exe
    1⤵
    • Executes dropped EXE
    • Suspicious use of AdjustPrivilegeToken
    PID:2808
  • C:\Users\Admin\AppData\Roaming\MasonClient.exe
    "C:\Users\Admin\AppData\Roaming\MasonClient.exe"
    1⤵
    • Executes dropped EXE
    • Suspicious use of AdjustPrivilegeToken
    PID:2200
  • C:\Users\Admin\AppData\Roaming\MasonClient.exe
    "C:\Users\Admin\AppData\Roaming\MasonClient.exe"
    1⤵
    • Executes dropped EXE
    • Suspicious use of AdjustPrivilegeToken
    PID:6024
  • C:\Users\Admin\AppData\Roaming\MasonClient.exe
    "C:\Users\Admin\AppData\Roaming\MasonClient.exe"
    1⤵
    • Executes dropped EXE
    • Suspicious use of AdjustPrivilegeToken
    PID:3452

Network

        MITRE ATT&CK Enterprise v16

        Replay Monitor

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        Downloads

        MasonClient.exe

        • Path C:\Users\Admin\AppData\Roaming\MasonClient.exe
        • Size 49KB
        • SHA256 64f36ad264c04537c28687e5ee00ae3dbd3462e126cfee473f87344417f88b00
        • MD5 SHA1 SHA512 SSDEEP TLSH

        memory/2808-9-0x00007FFAC0970000-0x00007FFAC1314000-memory.dmp

        memory/5840-0-0x00007FFAC0AFF000-0x00007FFAC0B00000-memory.dmp

        memory/5840-1-0x0000000000840000-0x0000000000852000-memory.dmp

        memory/5840-2-0x00007FFAC0970000-0x00007FFAC1314000-memory.dmp

        memory/5840-3-0x00007FFAC0970000-0x00007FFAC1314000-memory.dmp

        memory/5840-4-0x00007FFAC0970000-0x00007FFAC1314000-memory.dmp

        memory/5840-5-0x00007FFAC0970000-0x00007FFAC1314000-memory.dmp

        memory/5840-6-0x00007FFAC0970000-0x00007FFAC1314000-memory.dmp

        memory/5840-8-0x00007FFAC0970000-0x00007FFAC1314000-memory.dmp