Analysis

  • max time kernel
    149s
  • max time network
    147s
  • platform
    windows10-2004_x64
  • resource
    win10v2004-20260911-en
  • resource tags

    arch:x64arch:x86image:win10v2004-20260911-enlocale:en-usos:windows10-2004-x64systemwindows
  • submitted
    04/11/2026, 09:43

General

  • Target
    2026-11-03_b941a80d828332ba4689cf856222128d_amadey_elex_remcos_smoke-loader.exe
  • Size 15.0MB
  • Sample261104-lp8beazydv
  • SHA256 4a563a6d75de3775a3c51e949da78c6e5d0afcd9cdf871d08a70ee519a816d06
  • MD5 SHA1 SHA512 SSDEEP TLSH

Malware Config

Extracted

Family
  • tofsee

C2
  • quadoil.ru

  • lakeflex.ru

Signatures

  • Family: Tofsee

    Backdoor/botnet which carries out malicious activities based on commands from a C2 server.

  • Modifies Windows Firewall 2 TTPs 1 IoCs
  • Sets service image path in registry 3 TTPs 1 IoCs

    This determines the executable launched when a service starts. It can be used to establish persistence.

  • Checks computer location settings 2 TTPs 1 IoCs

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

  • Creates new service(s) 2 TTPs
  • Deletes itself 1 TTPs 1 IoCs
  • Executes dropped EXE 1 IoCs
  • Suspicious use of SetThreadContext 1 IoCs
  • Launches sc.exe 3 IoCs

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

  • Enumerates physical storage devices 1 TTPs

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

  • Event Triggered Execution: Netsh Helper DLL 1 TTPs 3 IoCs

    Netsh.exe (also referred to as Netshell) is a command-line scripting utility used to interact with the network configuration of a system.

  • Executes a command shell one-liner 1 TTPs 2 IoCs

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

  • Program crash 2 IoCs
  • System Location Discovery: System Language Discovery 1 TTPs 9 IoCs

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

  • Suspicious use of WriteProcessMemory 8 IoCs

Processes

  • C:\Users\Admin\AppData\Local\Temp\2026-11-03_b941a80d828332ba4689cf856222128d_amadey_elex_remcos_smoke-loader.exe
    "C:\Users\Admin\AppData\Local\Temp\2026-11-03_b941a80d828332ba4689cf856222128d_amadey_elex_remcos_smoke-loader.exe"
    1⤵
    • Checks computer location settings
    • System Location Discovery: System Language Discovery
    • Suspicious use of WriteProcessMemory
    PID:4916
    • C:\Windows\SysWOW64\cmd.exe
      "C:\Windows\System32\cmd.exe" /C mkdir C:\Windows\SysWOW64\zresshf\
      2⤵
      • Executes a command shell one-liner
      • System Location Discovery: System Language Discovery
      PID:3820
    • C:\Windows\SysWOW64\cmd.exe
      "C:\Windows\System32\cmd.exe" /C move /Y "C:\Users\Admin\AppData\Local\Temp\ydndrw.exe" C:\Windows\SysWOW64\zresshf\
      2⤵
      • Executes a command shell one-liner
      • System Location Discovery: System Language Discovery
      PID:4620
    • C:\Windows\SysWOW64\sc.exe
      "C:\Windows\System32\sc.exe" create zresshf binPath= "C:\Windows\SysWOW64\zresshf\ydndrw.exe /d\"C:\Users\Admin\AppData\Local\Temp\2026-11-03_b941a80d828332ba4689cf856222128d_amadey_elex_remcos_smoke-loader.exe\"" type= own start= auto DisplayName= "wifi support"
      2⤵
      • Launches sc.exe
      • System Location Discovery: System Language Discovery
      PID:3816
    • C:\Windows\SysWOW64\sc.exe
      "C:\Windows\System32\sc.exe" description zresshf "wifi internet conection"
      2⤵
      • Launches sc.exe
      • System Location Discovery: System Language Discovery
      PID:4876
    • C:\Windows\SysWOW64\sc.exe
      "C:\Windows\System32\sc.exe" start zresshf
      2⤵
      • Launches sc.exe
      • System Location Discovery: System Language Discovery
      PID:3960
    • C:\Windows\SysWOW64\netsh.exe
      "C:\Windows\System32\netsh.exe" advfirewall firewall add rule name="Host-process for services of Windows" dir=in action=allow program="C:\Windows\SysWOW64\svchost.exe" enable=yes>nul
      2⤵
      • Modifies Windows Firewall
      • Event Triggered Execution: Netsh Helper DLL
      • System Location Discovery: System Language Discovery
      PID:4528
    • C:\Windows\SysWOW64\WerFault.exe
      C:\Windows\SysWOW64\WerFault.exe -u -p 4916 -s 1296
      2⤵
      • Program crash
      PID:2864
  • C:\Windows\SysWOW64\zresshf\ydndrw.exe
    C:\Windows\SysWOW64\zresshf\ydndrw.exe /d"C:\Users\Admin\AppData\Local\Temp\2026-11-03_b941a80d828332ba4689cf856222128d_amadey_elex_remcos_smoke-loader.exe"
    1⤵
    • Executes dropped EXE
    • Suspicious use of SetThreadContext
    • System Location Discovery: System Language Discovery
    • Suspicious use of WriteProcessMemory
    PID:3312
    • C:\Windows\SysWOW64\svchost.exe
      svchost.exe
      2⤵
      • Sets service image path in registry
      • Deletes itself
      • System Location Discovery: System Language Discovery
      PID:2512
    • C:\Windows\SysWOW64\WerFault.exe
      C:\Windows\SysWOW64\WerFault.exe -u -p 3312 -s 536
      2⤵
      • Program crash
      PID:4080
  • C:\Windows\SysWOW64\WerFault.exe
    C:\Windows\SysWOW64\WerFault.exe -pss -s 456 -p 4916 -ip 4916
    1⤵
      PID:4672
    • C:\Windows\SysWOW64\WerFault.exe
      C:\Windows\SysWOW64\WerFault.exe -pss -s 452 -p 3312 -ip 3312
      1⤵
        PID:2916

      Network

            MITRE ATT&CK Enterprise v16

            Replay Monitor

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            Downloads

            ydndrw.exe

            • Path C:\Users\Admin\AppData\Local\Temp\ydndrw.exe
            • Size 10.6MB
            • SHA256 ec5d252d8a89ade39836c216d6091e9b243b2d508957d2b729f7631b6dcdb903
            • MD5 SHA1 SHA512 SSDEEP TLSH

            memory/2512-10-0x0000000000E40000-0x0000000000E55000-memory.dmp

            memory/2512-12-0x0000000000E40000-0x0000000000E55000-memory.dmp

            memory/2512-13-0x0000000000E40000-0x0000000000E55000-memory.dmp

            memory/3312-14-0x0000000000400000-0x0000000002B4D000-memory.dmp

            memory/4916-1-0x0000000002CF0000-0x0000000002DF0000-memory.dmp

            memory/4916-2-0x0000000004890000-0x00000000048A3000-memory.dmp

            memory/4916-8-0x0000000004890000-0x00000000048A3000-memory.dmp

            memory/4916-7-0x0000000000400000-0x0000000002B4D000-memory.dmp