Analysis

  • user interaction
    yes
  • max time kernel
    149s
  • 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
    17/08/2026, 09:07

General

  • Target
    client(4).exe
  • Size 21.4MB
  • Sample260817-k3t59sgp21
  • SHA256 7453159bfac8edb8223b06ce4105b98a92878a261488efc0c84c9e8627fb5e67
  • MD5 SHA1 SHA512 SSDEEP TLSH

Malware Config

Signatures

  • Family: Sparkrat

    Sparkrat is a cross-platfrom backdoor written in Golang.

  • family_sparkrat 1 IoCs

    Detects Sparkrat payload

  • Executes dropped EXE 2 IoCs
  • Drops file in System32 directory 1 IoCs
  • Launches sc.exe 2 IoCs

    Sc.exe is a Windows utlilty to control services on the system.

  • Command and Scripting Interpreter: PowerShell 1 TTPs 3 IoCs

    Using powershell.exe command.

  • Executes a command shell one-liner 1 TTPs 4 IoCs

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

  • Delays execution with timeout.exe 1 IoCs
  • Kills process with taskkill 1 IoCs
  • Modifies data under HKEY_USERS 40 IoCs
  • Modifies registry class 1 IoCs
  • Scheduled Task/Job: Scheduled Task 1 TTPs 10 IoCs

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

  • Suspicious behavior: EnumeratesProcesses 6 IoCs
  • Suspicious use of AdjustPrivilegeToken 7 IoCs
  • Suspicious use of SetWindowsHookEx 1 IoCs
  • Suspicious use of WriteProcessMemory 27 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\client(4).exe
    "C:\Users\Admin\AppData\Local\Temp\client(4).exe"
    1⤵
    • Suspicious behavior: EnumeratesProcesses
    • Suspicious use of AdjustPrivilegeToken
    • Suspicious use of WriteProcessMemory
    PID:3456
    • C:\Windows\system32\cmd.exe
      cmd ver
      2⤵
        PID:1240
      • C:\Windows\system32\taskkill.exe
        taskkill /F /IM UpdateService.exe /T
        2⤵
        • Kills process with taskkill
        • Suspicious use of AdjustPrivilegeToken
        PID:5756
      • C:\Windows\system32\schtasks.exe
        schtasks.exe /Delete /F /TN WinUpdateSvcWatchdog
        2⤵
          PID:2952
        • C:\Windows\system32\schtasks.exe
          schtasks.exe /Create /F /SC MINUTE /MO 1 /RU SYSTEM /RL HIGHEST /TN WinUpdateSvcWatchdog /TR "cmd.exe /C \"C:\ProgramData\Microsoft\Update\start_service.cmd\""
          2⤵
          • Scheduled Task/Job: Scheduled Task
          PID:5244
        • C:\Windows\system32\cmd.exe
          cmd.exe /C start /b "" C:\Users\Admin\AppData\Local\Temp\svc_cleanup_1786957715394634900.bat
          2⤵
          • Executes a command shell one-liner
          • Suspicious use of WriteProcessMemory
          PID:2736
          • C:\Windows\system32\cmd.exe
            C:\Windows\system32\cmd.exe /K C:\Users\Admin\AppData\Local\Temp\svc_cleanup_1786957715394634900.bat
            3⤵
            • Executes a command shell one-liner
            • Suspicious use of WriteProcessMemory
            PID:492
            • C:\Windows\system32\timeout.exe
              timeout /t 5 /nobreak
              4⤵
              • Delays execution with timeout.exe
              PID:5740
      • C:\ProgramData\Microsoft\Update\UpdateService.exe
        C:\ProgramData\Microsoft\Update\UpdateService.exe
        1⤵
        • Executes dropped EXE
        • Modifies data under HKEY_USERS
        • Suspicious behavior: EnumeratesProcesses
        • Suspicious use of AdjustPrivilegeToken
        • Suspicious use of WriteProcessMemory
        PID:1776
        • C:\Windows\system32\cmd.exe
          cmd ver
          2⤵
            PID:5336
          • C:\Windows\system32\schtasks.exe
            schtasks.exe /Create /F /SC MINUTE /MO 1 /RU SYSTEM /RL HIGHEST /TN WinUpdateSvcWatchdog /TR "cmd.exe /C \"C:\ProgramData\Microsoft\Update\start_service.cmd\""
            2⤵
            • Scheduled Task/Job: Scheduled Task
            PID:5860
          • C:\ProgramData\Microsoft\Update\UpdateService.exe
            "C:\ProgramData\Microsoft\Update\UpdateService.exe" --ui-only
            2⤵
            • Executes dropped EXE
            • Drops file in System32 directory
            • Suspicious behavior: EnumeratesProcesses
            • Suspicious use of AdjustPrivilegeToken
            • Suspicious use of WriteProcessMemory
            PID:3852
            • C:\Windows\system32\cmd.exe
              cmd ver
              3⤵
                PID:2456
            • C:\Windows\system32\schtasks.exe
              schtasks.exe /Create /F /SC MINUTE /MO 1 /RU SYSTEM /RL HIGHEST /TN WinUpdateSvcWatchdog /TR "cmd.exe /C \"C:\ProgramData\Microsoft\Update\start_service.cmd\""
              2⤵
              • Scheduled Task/Job: Scheduled Task
              PID:3404
            • C:\Windows\system32\schtasks.exe
              schtasks.exe /Create /F /SC MINUTE /MO 1 /RU SYSTEM /RL HIGHEST /TN WinUpdateSvcWatchdog /TR "cmd.exe /C \"C:\ProgramData\Microsoft\Update\start_service.cmd\""
              2⤵
              • Scheduled Task/Job: Scheduled Task
              PID:5564
            • C:\Windows\system32\schtasks.exe
              schtasks.exe /Create /F /SC MINUTE /MO 1 /RU SYSTEM /RL HIGHEST /TN WinUpdateSvcWatchdog /TR "cmd.exe /C \"C:\ProgramData\Microsoft\Update\start_service.cmd\""
              2⤵
              • Scheduled Task/Job: Scheduled Task
              PID:2460
            • C:\Windows\system32\conhost.exe
              \\?\C:\Windows\system32\conhost.exe --headless --width 120 --height 30 --signal 0x650 --server 0x60c
              2⤵
                PID:5572
              • C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe
                powershell.exe -NoLogo
                2⤵
                • Command and Scripting Interpreter: PowerShell
                PID:1620
              • C:\Windows\system32\conhost.exe
                \\?\C:\Windows\system32\conhost.exe --headless --width 120 --height 30 --signal 0x5e4 --server 0x608
                2⤵
                  PID:4488
                • C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe
                  powershell.exe -NoLogo
                  2⤵
                  • Command and Scripting Interpreter: PowerShell
                  PID:1628
                • C:\Windows\system32\schtasks.exe
                  schtasks.exe /Create /F /SC MINUTE /MO 1 /RU SYSTEM /RL HIGHEST /TN WinUpdateSvcWatchdog /TR "cmd.exe /C \"C:\ProgramData\Microsoft\Update\start_service.cmd\""
                  2⤵
                  • Scheduled Task/Job: Scheduled Task
                  PID:4796
                • C:\Windows\system32\conhost.exe
                  \\?\C:\Windows\system32\conhost.exe --headless --width 120 --height 30 --signal 0x69c --server 0x630
                  2⤵
                    PID:4136
                  • C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe
                    powershell.exe -NoLogo
                    2⤵
                    • Command and Scripting Interpreter: PowerShell
                    PID:4840
                  • C:\Windows\system32\schtasks.exe
                    schtasks.exe /Create /F /SC MINUTE /MO 1 /RU SYSTEM /RL HIGHEST /TN WinUpdateSvcWatchdog /TR "cmd.exe /C \"C:\ProgramData\Microsoft\Update\start_service.cmd\""
                    2⤵
                    • Scheduled Task/Job: Scheduled Task
                    PID:2300
                  • C:\Windows\system32\schtasks.exe
                    schtasks.exe /Create /F /SC MINUTE /MO 1 /RU SYSTEM /RL HIGHEST /TN WinUpdateSvcWatchdog /TR "cmd.exe /C \"C:\ProgramData\Microsoft\Update\start_service.cmd\""
                    2⤵
                    • Scheduled Task/Job: Scheduled Task
                    PID:228
                  • C:\Windows\system32\schtasks.exe
                    schtasks.exe /Create /F /SC MINUTE /MO 1 /RU SYSTEM /RL HIGHEST /TN WinUpdateSvcWatchdog /TR "cmd.exe /C \"C:\ProgramData\Microsoft\Update\start_service.cmd\""
                    2⤵
                    • Scheduled Task/Job: Scheduled Task
                    PID:5168
                  • C:\Windows\system32\schtasks.exe
                    schtasks.exe /Create /F /SC MINUTE /MO 1 /RU SYSTEM /RL HIGHEST /TN WinUpdateSvcWatchdog /TR "cmd.exe /C \"C:\ProgramData\Microsoft\Update\start_service.cmd\""
                    2⤵
                    • Scheduled Task/Job: Scheduled Task
                    PID:2292
                • C:\Windows\system32\cmd.exe
                  cmd.exe
                  1⤵
                    PID:5948
                  • C:\Windows\system32\cmd.exe
                    cmd.exe /C "C:\ProgramData\Microsoft\Update\start_service.cmd"
                    1⤵
                    • Executes a command shell one-liner
                    • Suspicious use of WriteProcessMemory
                    PID:1632
                    • C:\Windows\system32\sc.exe
                      sc start WinUpdateSvc
                      2⤵
                      • Launches sc.exe
                      PID:3864
                  • C:\Windows\SystemApps\MicrosoftWindows.Client.CBS_cw5n1h2txyewy\MiniSearchHost.exe
                    "C:\Windows\SystemApps\MicrosoftWindows.Client.CBS_cw5n1h2txyewy\MiniSearchHost.exe" -ServerName:MiniSearchUI.AppXj3y73at8fy1htwztzxs68sxx1v7cksp7.mca
                    1⤵
                    • Modifies registry class
                    • Suspicious use of SetWindowsHookEx
                    PID:2508
                  • C:\Windows\system32\cmd.exe
                    cmd.exe /C "C:\ProgramData\Microsoft\Update\start_service.cmd"
                    1⤵
                    • Executes a command shell one-liner
                    • Suspicious use of WriteProcessMemory
                    PID:5684
                    • C:\Windows\system32\sc.exe
                      sc start WinUpdateSvc
                      2⤵
                      • Launches sc.exe
                      PID:5232

                  Network

                        MITRE ATT&CK Enterprise v16

                        Replay Monitor

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                        Downloads

                        UpdateService.exe

                        • Path C:\ProgramData\Microsoft\Update\UpdateService.exe
                        • Size 21.4MB
                        • SHA256 7453159bfac8edb8223b06ce4105b98a92878a261488efc0c84c9e8627fb5e67
                        • MD5 SHA1 SHA512 SSDEEP TLSH

                        client.log

                        • Path C:\ProgramData\Microsoft\Update\client.log
                        • Size 6KB
                        • SHA256 b63b7b6690303b537662302d67173b6b31c6192843e645c586cadcf30d65f230
                        • MD5 SHA1 SHA512 SSDEEP TLSH

                        client.log

                        • Path C:\ProgramData\Microsoft\Update\client.log
                        • Size 4KB
                        • SHA256 94135b7fc6b1a1e63ee8ab109a4e0deedd2b8b4ba8be2f21374d1fce537a24dc
                        • MD5 SHA1 SHA512 SSDEEP TLSH

                        start_service.cmd

                        • Path C:\ProgramData\Microsoft\Update\start_service.cmd
                        • Size 44B
                        • SHA256 288893fb4b5598c4904c5af6fe12662560e574e5cbd0734ac42d94268d2710e9
                        • MD5 SHA1 SHA512

                        svc_cleanup_1786957715394634900.bat

                        • Path C:\Users\Admin\AppData\Local\Temp\svc_cleanup_1786957715394634900.bat
                        • Size 143B
                        • SHA256 5c4e0d74e098d0baacbb15a01fa9725d88f5af1432975ba4b5539b5def0cf896
                        • MD5 SHA1 SHA512 TLSH