Analysis

  • max time kernel
    147s
  • max time network
    149s
  • platform
    windows10-2004_x64
  • resource
    win10v2004-20240226-en
  • resource tags

    arch:x64arch:x86image:win10v2004-20240226-enlocale:en-usos:windows10-2004-x64system
  • submitted
    02/04/2024, 10:12

General

  • Target
    fd79a1b3b18fca2696c2c58f290a4dadb97e3cdcd6e98d14a63ac3f4a1f2e351.exe
  • Size 288KB
  • Sample240402-l8v57aed8v
  • SHA256 fd79a1b3b18fca2696c2c58f290a4dadb97e3cdcd6e98d14a63ac3f4a1f2e351
  • MD5 SHA1 SHA512 SSDEEP

Malware Config

Extracted

Family
  • tofsee

C2
  • vanaheim.cn

  • jotunheim.name

Signatures

  • Tofsee

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

  • Creates new service(s) 1 TTPs
  • Modifies Windows Firewall 2 TTPs 1 IoCs
  • Sets service image path in registry 2 TTPs 1 IoCs
  • Checks computer location settings 2 TTPs 1 IoCs

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

  • Deletes itself 1 IoCs
  • Executes dropped EXE 1 IoCs
  • Drops file in System32 directory 2 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).

  • Program crash 2 IoCs
  • Modifies data under HKEY_USERS 7 IoCs
  • Suspicious use of WriteProcessMemory 23 IoCs

Processes

  • C:\Users\Admin\AppData\Local\Temp\fd79a1b3b18fca2696c2c58f290a4dadb97e3cdcd6e98d14a63ac3f4a1f2e351.exe
    "C:\Users\Admin\AppData\Local\Temp\fd79a1b3b18fca2696c2c58f290a4dadb97e3cdcd6e98d14a63ac3f4a1f2e351.exe"
    1⤵
    • Checks computer location settings
    • Suspicious use of WriteProcessMemory
    PID:3212
    • C:\Windows\SysWOW64\cmd.exe
      "C:\Windows\System32\cmd.exe" /C mkdir C:\Windows\SysWOW64\avrwoknz\
      2⤵
        PID:672
      • C:\Windows\SysWOW64\cmd.exe
        "C:\Windows\System32\cmd.exe" /C move /Y "C:\Users\Admin\AppData\Local\Temp\bihuccko.exe" C:\Windows\SysWOW64\avrwoknz\
        2⤵
          PID:2280
        • C:\Windows\SysWOW64\sc.exe
          "C:\Windows\System32\sc.exe" create avrwoknz binPath= "C:\Windows\SysWOW64\avrwoknz\bihuccko.exe /d\"C:\Users\Admin\AppData\Local\Temp\fd79a1b3b18fca2696c2c58f290a4dadb97e3cdcd6e98d14a63ac3f4a1f2e351.exe\"" type= own start= auto DisplayName= "wifi support"
          2⤵
          • Launches sc.exe
          PID:112
        • C:\Windows\SysWOW64\sc.exe
          "C:\Windows\System32\sc.exe" description avrwoknz "wifi internet conection"
          2⤵
          • Launches sc.exe
          PID:3620
        • C:\Windows\SysWOW64\sc.exe
          "C:\Windows\System32\sc.exe" start avrwoknz
          2⤵
          • Launches sc.exe
          PID:840
        • 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
          PID:2100
        • C:\Windows\SysWOW64\WerFault.exe
          C:\Windows\SysWOW64\WerFault.exe -u -p 3212 -s 1152
          2⤵
          • Program crash
          PID:2832
      • C:\Windows\SysWOW64\avrwoknz\bihuccko.exe
        C:\Windows\SysWOW64\avrwoknz\bihuccko.exe /d"C:\Users\Admin\AppData\Local\Temp\fd79a1b3b18fca2696c2c58f290a4dadb97e3cdcd6e98d14a63ac3f4a1f2e351.exe"
        1⤵
        • Executes dropped EXE
        • Suspicious use of SetThreadContext
        • Suspicious use of WriteProcessMemory
        PID:4504
        • C:\Windows\SysWOW64\svchost.exe
          svchost.exe
          2⤵
          • Sets service image path in registry
          • Deletes itself
          • Drops file in System32 directory
          • Modifies data under HKEY_USERS
          PID:644
        • C:\Windows\SysWOW64\WerFault.exe
          C:\Windows\SysWOW64\WerFault.exe -u -p 4504 -s 528
          2⤵
          • Program crash
          PID:4128
      • C:\Windows\SysWOW64\WerFault.exe
        C:\Windows\SysWOW64\WerFault.exe -pss -s 468 -p 4504 -ip 4504
        1⤵
          PID:2496
        • C:\Windows\SysWOW64\WerFault.exe
          C:\Windows\SysWOW64\WerFault.exe -pss -s 504 -p 3212 -ip 3212
          1⤵
            PID:5104

          Network

                MITRE ATT&CK Enterprise v15

                Replay Monitor

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                Downloads

                bihuccko.exe

                • Path C:\Users\Admin\AppData\Local\Temp\bihuccko.exe
                • Size 7.6MB
                • SHA256 743e46dfed93ca8e83d39dc2ca832f79b56f5f4806031a591909fad76d4d86d9
                • MD5 SHA1 SHA512 SSDEEP

                bihuccko.exe

                • Path C:\Windows\SysWOW64\avrwoknz\bihuccko.exe
                • Size 7.1MB
                • SHA256 5d4824ea067597a63cd9ba628033f1da8fa37342d59d67efadfa3647a80fc3b2
                • MD5 SHA1 SHA512 SSDEEP

                memory/644-45-0x0000000002160000-0x0000000002170000-memory.dmp

                memory/644-44-0x0000000002160000-0x0000000002170000-memory.dmp

                memory/644-59-0x0000000000B90000-0x0000000000BA5000-memory.dmp

                memory/644-20-0x0000000002A00000-0x0000000002C0F000-memory.dmp

                memory/644-23-0x0000000002A00000-0x0000000002C0F000-memory.dmp

                memory/644-14-0x0000000000B90000-0x0000000000BA5000-memory.dmp

                memory/644-24-0x0000000000FF0000-0x0000000000FF6000-memory.dmp

                memory/644-30-0x0000000002160000-0x0000000002170000-memory.dmp

                memory/644-8-0x0000000000B90000-0x0000000000BA5000-memory.dmp

                memory/644-43-0x0000000002160000-0x0000000002170000-memory.dmp

                memory/644-18-0x0000000000B90000-0x0000000000BA5000-memory.dmp

                memory/644-27-0x0000000002160000-0x0000000002170000-memory.dmp

                memory/644-47-0x00000000021F0000-0x00000000021F5000-memory.dmp

                memory/644-51-0x0000000007980000-0x0000000007D8B000-memory.dmp

                memory/644-55-0x0000000002FD0000-0x0000000002FD7000-memory.dmp

                memory/644-54-0x0000000007980000-0x0000000007D8B000-memory.dmp

                memory/644-50-0x00000000021F0000-0x00000000021F5000-memory.dmp

                memory/644-46-0x0000000002160000-0x0000000002170000-memory.dmp

                memory/644-31-0x0000000002160000-0x0000000002170000-memory.dmp

                memory/644-32-0x0000000002160000-0x0000000002170000-memory.dmp

                memory/644-17-0x0000000000B90000-0x0000000000BA5000-memory.dmp

                memory/644-42-0x0000000002160000-0x0000000002170000-memory.dmp

                memory/644-41-0x0000000002160000-0x0000000002170000-memory.dmp

                memory/644-40-0x0000000002160000-0x0000000002170000-memory.dmp

                memory/644-39-0x0000000002160000-0x0000000002170000-memory.dmp

                memory/644-38-0x0000000002160000-0x0000000002170000-memory.dmp

                memory/644-37-0x0000000002160000-0x0000000002170000-memory.dmp

                memory/644-36-0x0000000002160000-0x0000000002170000-memory.dmp

                memory/644-35-0x0000000002160000-0x0000000002170000-memory.dmp

                memory/644-34-0x0000000002160000-0x0000000002170000-memory.dmp

                memory/644-33-0x0000000002160000-0x0000000002170000-memory.dmp

                memory/3212-2-0x0000000002060000-0x0000000002073000-memory.dmp

                memory/3212-3-0x0000000000400000-0x0000000000450000-memory.dmp

                memory/3212-16-0x0000000000400000-0x0000000000450000-memory.dmp

                memory/3212-1-0x00000000005C0000-0x00000000006C0000-memory.dmp

                memory/4504-12-0x0000000000400000-0x0000000000450000-memory.dmp

                memory/4504-9-0x00000000004B0000-0x00000000005B0000-memory.dmp

                memory/4504-10-0x0000000000D20000-0x0000000000D33000-memory.dmp