Resubmissions

01/06/2026, 03:37

260601-d6wpyaes2l7

01/06/2026, 02:34

260601-c2sl2sbx617

01/06/2026, 02:31

260601-czq1fabx5x7

Analysis

  • max time kernel
    148s
  • max time network
    150s
  • platform
    windows11-21h2_x64
  • resource
    win11-20260513-en
  • resource tags

    arch:x64arch:x86image:win11-20260513-enlocale:en-usos:windows11-21h2-x64systemwindows
  • submitted
    01/06/2026, 02:34

General

  • Target
    MasonChess.exe
  • Size 1.3MB
  • Sample260601-c2sl2sbx61
  • SHA256 9be0c047cea06ab24bdb1711ca7d4608e179826d079206ed36a1aea830cc5149
  • MD5 SHA1 SHA512 SSDEEP TLSH

Malware Config

Signatures

  • Executes dropped EXE 2 IoCs
  • 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.

  • Enumerates physical storage devices 1 TTPs

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

  • 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.

  • Suspicious use of AdjustPrivilegeToken 4 IoCs
  • Suspicious use of FindShellTrayWindow 1 IoCs
  • Suspicious use of SetWindowsHookEx 1 IoCs
  • Suspicious use of WriteProcessMemory 4 IoCs

Processes

  • C:\Users\Admin\AppData\Local\Temp\MasonChess.exe
    "C:\Users\Admin\AppData\Local\Temp\MasonChess.exe"
    1⤵
    • Writes to the Master Boot Record (MBR)
    • System Location Discovery: System Language Discovery
    • Suspicious use of AdjustPrivilegeToken
    • Suspicious use of FindShellTrayWindow
    • Suspicious use of SetWindowsHookEx
    • Suspicious use of WriteProcessMemory
    PID:2904
    • C:\Users\Admin\AppData\Local\Temp\nasm.exe
      "nasm.exe" -f bin mbr_temp.asm -o mbr_temp.bin
      2⤵
      • Executes dropped EXE
      • System Location Discovery: System Language Discovery
      PID:4768
    • C:\Users\Admin\AppData\Local\Temp\nasm.exe
      "nasm.exe" -f bin mbr_temp.asm -o mbr_temp.bin
      2⤵
      • Executes dropped EXE
      PID:2896
    • C:\Windows\SysWOW64\cmd.exe
      "C:\Windows\System32\cmd.exe" /k reg delete HKCR /f
      2⤵
      • System Location Discovery: System Language Discovery
      • Suspicious use of WriteProcessMemory
      PID:4164
      • C:\Windows\SysWOW64\reg.exe
        reg delete HKCR /f
        3⤵
        • System Location Discovery: System Language Discovery
        PID:1856
  • C:\Windows\system32\AUDIODG.EXE
    C:\Windows\system32\AUDIODG.EXE 0x0000000000000480 0x00000000000004EC
    1⤵
    • Suspicious use of AdjustPrivilegeToken
    PID:2756

Network

        MITRE ATT&CK Enterprise v16

        Replay Monitor

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        Downloads

        mbr_temp.asm

        • Path C:\Users\Admin\AppData\Local\Temp\mbr_temp.asm
        • Size 790B
        • SHA256 45a342877c16247c906eedf06e88f3e17b565c2f29902f065913abb12d324654
        • MD5 SHA1 SHA512 TLSH

        mbr_temp.asm

        • Path C:\Users\Admin\AppData\Local\Temp\mbr_temp.asm
        • Size 789B
        • SHA256 4b878639dc0f71ebcf7279dc54342528363a818cc7af559ab1093ff0b3d6022d
        • MD5 SHA1 SHA512 TLSH

        mbr_temp.bin

        • Path C:\Users\Admin\AppData\Local\Temp\mbr_temp.bin
        • Size 512B
        • SHA256 74cc853be8142f1bb27c3e1b232197d07755cd5d53075e44b64dd7cd3a6ae084
        • MD5 SHA1 SHA512 TLSH

        mbr_temp.bin

        • Path C:\Users\Admin\AppData\Local\Temp\mbr_temp.bin
        • Size 512B
        • SHA256 d8ee48365b57e29fee8895ac549ca58730e9c14bc5eafb3d11c144b71d3d7009
        • MD5 SHA1 SHA512 TLSH

        nasm.exe

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

        memory/2896-22-0x0000000000400000-0x0000000000539000-memory.dmp

        memory/2904-3-0x0000000005A70000-0x0000000005A80000-memory.dmp

        memory/2904-4-0x0000000005A90000-0x0000000005A9A000-memory.dmp

        memory/2904-15-0x0000000005A70000-0x0000000005A80000-memory.dmp

        memory/2904-0-0x0000000000E90000-0x0000000000FE2000-memory.dmp

        memory/2904-2-0x0000000005AB0000-0x0000000005B42000-memory.dmp

        memory/2904-1-0x0000000006130000-0x00000000066D6000-memory.dmp

        memory/4768-13-0x0000000000400000-0x0000000000539000-memory.dmp