Overview

overview

10

Static

static

10

MasonClient.exe

windows10-2004-x64

10

MasonClient.exe

windows10-ltsc_2021-x64

MasonClient.exe

windows11-21h2-x64

MasonClient.exe

windows11-ltsc_2024-x64

10

Analysis

  • user interaction
    yes
  • max time kernel
    46s
  • max time network
    121s
  • platform
    windows11-21h2_x64
  • resource
    win11-20260911-en
  • resource tags

    arch:x64arch:x86image:win11-20260911-enlocale:en-usos:windows11-21h2-x64systemwindows
  • submitted
    16/10/2026, 14:29

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Errors

Reason
Machine shutdown

General

  • Target
    MasonClient.exe
  • Size 48KB
  • Sample261016-rtj29svyct
  • SHA256 25596e7b6ad36b42fc82b25876b7100f60dedbc219e66e5457a00fb8a96b1bf8
  • MD5 SHA1 SHA512 SSDEEP TLSH
Score
10/10
bootkitdefense_evasiondiscoveryexecutionneptuneratpersistenceprivilege_escalationtrojan

Malware Config

Extracted

Family

  • neptunerat

C2

  • eaf6677858-52804.portmap.host:52804

Attributes
  • filename

    USB.exe

  • group

    MasonGroup

  • key

    zmW7g49AZ2nXv9Rs

  • rat_name

    MasonRAT

Signatures

  • Family: NeptuneRAT, MasonRAT

    NeptuneRAT aka MasonRAT is a trojan written in C#.

    trojanneptunerat
  • Detects NeptuneRAT stealer 2 IoCs
  • Event Triggered Execution: Component Object Model Hijacking 1 TTPs

    Adversaries may establish persistence by executing malicious content triggered by hijacked references to Component Object Model (COM) objects.

    persistenceprivilege_escalation
  • Executes dropped EXE 2 IoCs
  • Modifies system executable filetype association 2 TTPs 34 IoCs
    persistence
  • Contacts third-party web service commonly abused for C2 1 TTPs 2 IoCs

    Legitimate web (hosting) services can be abused by malware authors to host malware or C2s.

  • Writes to the Master Boot Record (MBR) 1 TTPs 1 IoCs

    Bootkits write to the MBR to gain persistence at a level below the operating system.

    bootkitpersistence
  • Enumerates video capture drivers 2 TTPs 1 IoCs

    Queries the legacy Video for Windows capture drivers. This is commonly abused by RATs to check for available webcams on the system before reporting to their C2.

    discoverydefense_evasion
  • Enumerates physical storage devices 1 TTPs

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

  • Executes a command shell one-liner 1 TTPs 1 IoCs

    Execution of a cmd.exe one-liner (/c "close" or /k "keep") is a common script/loader stage.

    execution
  • 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.

    discovery
  • System Location Discovery: System Language Discovery 1 TTPs 4 IoCs

    Attempt gather information about the system language of a victim in order to infer the geographical location of that host.

    discovery
  • Modifies registry class 64 IoCs
  • Suspicious use of AdjustPrivilegeToken 5 IoCs
  • Suspicious use of WriteProcessMemory 4 IoCs

Processes

  • C:\Users\Admin\AppData\Local\Temp\MasonClient.exe
    "C:\Users\Admin\AppData\Local\Temp\MasonClient.exe"
    1⤵
    • Enumerates video capture drivers
    • Reads the TCP/IP host and domain name from the registry
    • Suspicious use of AdjustPrivilegeToken
    • Suspicious use of WriteProcessMemory
    PID:3128
    • C:\Users\Admin\AppData\Local\Temp\tmp51C0.tmp.exe
      "C:\Users\Admin\AppData\Local\Temp\tmp51C0.tmp.exe"
      2⤵
      • Executes dropped EXE
      • Writes to the Master Boot Record (MBR)
      • System Location Discovery: System Language Discovery
      • Suspicious use of AdjustPrivilegeToken
      • Suspicious use of WriteProcessMemory
      PID:1552
      • C:\Users\Admin\AppData\Local\Temp\nasm.exe
        "nasm.exe" -f bin mbr_temp.asm -o mbr_temp.bin
        3⤵
        • Executes dropped EXE
        • System Location Discovery: System Language Discovery
        PID:1780
      • C:\Windows\SysWOW64\cmd.exe
        "C:\Windows\System32\cmd.exe" /c reg delete HKCR /f
        3⤵
        • Executes a command shell one-liner
        • System Location Discovery: System Language Discovery
        • Suspicious use of WriteProcessMemory
        PID:5312
        • C:\Windows\SysWOW64\reg.exe
          reg delete HKCR /f
          4⤵
          • Modifies system executable filetype association
          • System Location Discovery: System Language Discovery
          • Modifies registry class
          PID:5304
  • C:\Windows\system32\AUDIODG.EXE
    C:\Windows\system32\AUDIODG.EXE 0x0000000000000494 0x00000000000004CC
    1⤵
    • Suspicious use of AdjustPrivilegeToken
    PID:2300

Network

        MITRE ATT&CK Enterprise v16

        Reconnaissance

        Resource Development

        Initial Access

        Execution

        Command and Scripting Interpreter

        1
        T1059

        Windows Command Shell

        1
        T1059.003

        Persistence

        Event Triggered Execution

        2
        T1546

        Change Default File Association

        1
        T1546.001

        Component Object Model Hijacking

        1
        T1546.015

        Pre-OS Boot

        1
        T1542

        Bootkit

        1
        T1542.003

        Privilege Escalation

        Event Triggered Execution

        2
        T1546

        Change Default File Association

        1
        T1546.001

        Component Object Model Hijacking

        1
        T1546.015

        Defense Evasion

        Modify Registry

        1
        T1112

        Pre-OS Boot

        1
        T1542

        Bootkit

        1
        T1542.003

        Credential Access

        Discovery

        Peripheral Device Discovery

        1
        T1120

        System Information Discovery

        1
        T1082

        System Location Discovery

        1
        T1614

        System Language Discovery

        1
        T1614.001

        System Network Configuration Discovery

        1
        T1016

        Lateral Movement

        Collection

        Video Capture

        1
        T1125

        Command and Control

        Web Service

        1
        T1102

        Exfiltration

        Impact

        Replay Monitor

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        Downloads

        mbr_temp.asm
        • Path C:\Users\Admin\AppData\Local\Temp\mbr_temp.asm
        • Size 1KB
        • SHA256 9fdfd968643c046a87defa558840a6a523324d8b7d447deb5cd089ab7e456317
        • MD5 SHA1 SHA512 TLSH
        Submit Download

        mbr_temp.bin
        • Path C:\Users\Admin\AppData\Local\Temp\mbr_temp.bin
        • Size 512B
        • SHA256 032c085f82cde3370e27119e29392d0bec4df704a6c431e9461f8bf1a32a5a06
        • MD5 SHA1 SHA512 TLSH
        Submit Download

        nasm.exe
        • Path C:\Users\Admin\AppData\Local\Temp\nasm.exe
        • Size 1.2MB
        • SHA256 a4735165141570d966b577d594c0541c29baed4978078c1c7237b855f8592a87
        • MD5 SHA1 SHA512 SSDEEP TLSH
        Submit Download

        tmp51C0.tmp.exe
        • Path C:\Users\Admin\AppData\Local\Temp\tmp51C0.tmp.exe
        • Size 1.2MB
        • SHA256 2342b3d3120400baea76a500a710fc239ea8d1c587459c4c20bc070e44281c27
        • MD5 SHA1 SHA512 SSDEEP TLSH
        Submit Download

        memory/1552-14-0x00000000003A0000-0x00000000004E0000-memory.dmp
        Download

        memory/1552-15-0x0000000005060000-0x0000000005070000-memory.dmp
        Download

        memory/1552-28-0x00000000058B0000-0x0000000005942000-memory.dmp
        Download

        memory/1552-29-0x0000000005060000-0x0000000005070000-memory.dmp
        Download

        memory/1780-23-0x0000000000400000-0x0000000000539000-memory.dmp
        Download

        memory/3128-0-0x0000000000A60000-0x0000000000A72000-memory.dmp
        Download

        memory/3128-1-0x000000001CE20000-0x000000001CE30000-memory.dmp
        Download

        memory/3128-2-0x000000001CE20000-0x000000001CE30000-memory.dmp
        Download