Analysis

  • max time kernel
    147s
  • max time network
    138s
  • platform
    windows10_x64
  • resource
    win10-en
  • submitted
    08/09/2021, 09:07

General

  • Target
    a8701b8d256bbccb00be92735e6b98f258d79efb875d8839e1c0ce09d16c3733.exe
  • Size 797KB
  • Sample210908-k3cafshdal
  • SHA256 a8701b8d256bbccb00be92735e6b98f258d79efb875d8839e1c0ce09d16c3733
  • MD5 SHA1 SHA512

Malware Config

Extracted

Family
  • vidar

Version
  • 40.5

Botnet
  • 517

C2
  • https://gheorghip.tumblr.com/

Attributes
  • profile_id

    517

Signatures

  • Detected Djvu ransomeware 6 IoCs
  • Djvu Ransomware

    Ransomware which is a variant of the STOP family.

  • Vidar

    Vidar is an infostealer based on Arkei stealer.

  • suricata: ET MALWARE Potential Dridex.Maldoc Minimal Executable Request

    suricata: ET MALWARE Potential Dridex.Maldoc Minimal Executable Request

  • suricata: ET MALWARE Suspicious Zipped Filename in Outbound POST Request (Passwords.txt)

    suricata: ET MALWARE Suspicious Zipped Filename in Outbound POST Request (Passwords.txt)

  • suricata: ET MALWARE Vidar/Arkei Stealer Client Data Upload

    suricata: ET MALWARE Vidar/Arkei Stealer Client Data Upload

  • suricata: ET MALWARE Vidar/Arkei/Megumin/Oski Stealer Data Exfil

    suricata: ET MALWARE Vidar/Arkei/Megumin/Oski Stealer Data Exfil

  • Vidar Stealer 5 IoCs
  • Downloads MZ/PE file
  • Executes dropped EXE 8 IoCs
  • Loads dropped DLL 2 IoCs
  • Modifies file permissions 1 TTPs 1 IoCs
  • Reads user/profile data of web browsers 2 TTPs

    Infostealers often target stored browser data, which can include saved credentials etc.

  • Accesses 2FA software files, possible credential harvesting 2 TTPs
  • Accesses cryptocurrency files/wallets, possible credential harvesting 2 TTPs
  • Adds Run key to start application 2 TTPs 1 IoCs
  • Checks installed software on the system 1 TTPs

    Looks up Uninstall key entries in the registry to enumerate software on the system.

  • Looks up external IP address via web service 3 IoCs

    Uses a legitimate IP lookup service to find the infected system's external IP.

  • Suspicious use of SetThreadContext 6 IoCs
  • Enumerates physical storage devices 1 TTPs

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

  • Checks processor information in registry 2 TTPs 2 IoCs

    Processor information is often read in order to detect sandboxing environments.

  • Creates scheduled task(s) 1 TTPs 2 IoCs

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

  • Delays execution with timeout.exe 1 IoCs
  • Kills process with taskkill 1 IoCs
  • Modifies system certificate store 2 TTPs 2 IoCs
  • Suspicious behavior: EnumeratesProcesses 12 IoCs
  • Suspicious use of AdjustPrivilegeToken 1 IoCs
  • Suspicious use of WriteProcessMemory 64 IoCs

Processes

  • C:\Users\Admin\AppData\Local\Temp\a8701b8d256bbccb00be92735e6b98f258d79efb875d8839e1c0ce09d16c3733.exe
    "C:\Users\Admin\AppData\Local\Temp\a8701b8d256bbccb00be92735e6b98f258d79efb875d8839e1c0ce09d16c3733.exe"
    1⤵
    • Suspicious use of SetThreadContext
    • Suspicious use of WriteProcessMemory
    PID:3008
    • C:\Users\Admin\AppData\Local\Temp\a8701b8d256bbccb00be92735e6b98f258d79efb875d8839e1c0ce09d16c3733.exe
      "C:\Users\Admin\AppData\Local\Temp\a8701b8d256bbccb00be92735e6b98f258d79efb875d8839e1c0ce09d16c3733.exe"
      2⤵
      • Adds Run key to start application
      • Modifies system certificate store
      • Suspicious behavior: EnumeratesProcesses
      • Suspicious use of WriteProcessMemory
      PID:3752
      • C:\Windows\SysWOW64\icacls.exe
        icacls "C:\Users\Admin\AppData\Local\c32269d6-2b91-4dd1-9e99-a17c4dba8821" /deny *S-1-1-0:(OI)(CI)(DE,DC)
        3⤵
        • Modifies file permissions
        PID:3596
      • C:\Users\Admin\AppData\Local\Temp\a8701b8d256bbccb00be92735e6b98f258d79efb875d8839e1c0ce09d16c3733.exe
        "C:\Users\Admin\AppData\Local\Temp\a8701b8d256bbccb00be92735e6b98f258d79efb875d8839e1c0ce09d16c3733.exe" --Admin IsNotAutoStart IsNotTask
        3⤵
        • Suspicious use of SetThreadContext
        • Suspicious use of WriteProcessMemory
        PID:3296
        • C:\Users\Admin\AppData\Local\Temp\a8701b8d256bbccb00be92735e6b98f258d79efb875d8839e1c0ce09d16c3733.exe
          "C:\Users\Admin\AppData\Local\Temp\a8701b8d256bbccb00be92735e6b98f258d79efb875d8839e1c0ce09d16c3733.exe" --Admin IsNotAutoStart IsNotTask
          4⤵
          • Suspicious behavior: EnumeratesProcesses
          • Suspicious use of WriteProcessMemory
          PID:2112
          • C:\Users\Admin\AppData\Local\26c5a968-e556-4558-acda-f5372983931e\build2.exe
            "C:\Users\Admin\AppData\Local\26c5a968-e556-4558-acda-f5372983931e\build2.exe"
            5⤵
            • Executes dropped EXE
            • Suspicious use of SetThreadContext
            • Suspicious use of WriteProcessMemory
            PID:3120
            • C:\Users\Admin\AppData\Local\26c5a968-e556-4558-acda-f5372983931e\build2.exe
              "C:\Users\Admin\AppData\Local\26c5a968-e556-4558-acda-f5372983931e\build2.exe"
              6⤵
              • Executes dropped EXE
              • Loads dropped DLL
              • Checks processor information in registry
              • Suspicious behavior: EnumeratesProcesses
              • Suspicious use of WriteProcessMemory
              PID:3020
              • C:\Windows\SysWOW64\cmd.exe
                "C:\Windows\System32\cmd.exe" /c taskkill /im build2.exe /f & timeout /t 6 & del /f /q "C:\Users\Admin\AppData\Local\26c5a968-e556-4558-acda-f5372983931e\build2.exe" & del C:\ProgramData\*.dll & exit
                7⤵
                • Suspicious use of WriteProcessMemory
                PID:3944
                • C:\Windows\SysWOW64\taskkill.exe
                  taskkill /im build2.exe /f
                  8⤵
                  • Kills process with taskkill
                  • Suspicious use of AdjustPrivilegeToken
                  PID:2964
                • C:\Windows\SysWOW64\timeout.exe
                  timeout /t 6
                  8⤵
                  • Delays execution with timeout.exe
                  PID:3968
          • C:\Users\Admin\AppData\Local\26c5a968-e556-4558-acda-f5372983931e\build3.exe
            "C:\Users\Admin\AppData\Local\26c5a968-e556-4558-acda-f5372983931e\build3.exe"
            5⤵
            • Executes dropped EXE
            • Suspicious use of SetThreadContext
            • Suspicious use of WriteProcessMemory
            PID:3580
            • C:\Users\Admin\AppData\Local\26c5a968-e556-4558-acda-f5372983931e\build3.exe
              "C:\Users\Admin\AppData\Local\26c5a968-e556-4558-acda-f5372983931e\build3.exe"
              6⤵
              • Executes dropped EXE
              • Suspicious use of WriteProcessMemory
              PID:2276
              • C:\Windows\SysWOW64\schtasks.exe
                /C /create /F /sc minute /mo 1 /tn "Azure-Update-Task" /tr "C:\Users\Admin\AppData\Roaming\Microsoft\Network\mstsca.exe"
                7⤵
                • Creates scheduled task(s)
                PID:2628
  • C:\Users\Admin\AppData\Roaming\Microsoft\Network\mstsca.exe
    C:\Users\Admin\AppData\Roaming\Microsoft\Network\mstsca.exe
    1⤵
    • Executes dropped EXE
    • Suspicious use of SetThreadContext
    • Suspicious use of WriteProcessMemory
    PID:2364
    • C:\Users\Admin\AppData\Roaming\Microsoft\Network\mstsca.exe
      C:\Users\Admin\AppData\Roaming\Microsoft\Network\mstsca.exe
      2⤵
      • Executes dropped EXE
      PID:3844
      • C:\Windows\SysWOW64\schtasks.exe
        /C /create /F /sc minute /mo 1 /tn "Azure-Update-Task" /tr "C:\Users\Admin\AppData\Roaming\Microsoft\Network\mstsca.exe"
        3⤵
        • Creates scheduled task(s)
        PID:2468
  • C:\Users\Admin\AppData\Roaming\Microsoft\Network\mstsca.exe
    C:\Users\Admin\AppData\Roaming\Microsoft\Network\mstsca.exe
    1⤵
    • Executes dropped EXE
    • Suspicious use of SetThreadContext
    PID:1116
    • C:\Users\Admin\AppData\Roaming\Microsoft\Network\mstsca.exe
      C:\Users\Admin\AppData\Roaming\Microsoft\Network\mstsca.exe
      2⤵
      • Executes dropped EXE
      PID:3936

Network

        MITRE ATT&CK Enterprise v6

        Replay Monitor

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        Downloads

        memory/1116-168-0x0000000003250000-0x000000000339A000-memory.dmp

        memory/2112-124-0x0000000000400000-0x0000000000537000-memory.dmp

        memory/2276-140-0x0000000000400000-0x0000000000406000-memory.dmp

        memory/2276-145-0x0000000000400000-0x0000000000406000-memory.dmp

        memory/2364-163-0x0000000003330000-0x0000000003334000-memory.dmp

        memory/3008-117-0x00000000049A0000-0x0000000004ABB000-memory.dmp

        memory/3020-132-0x0000000000400000-0x00000000004D5000-memory.dmp

        memory/3020-136-0x0000000000400000-0x00000000004D5000-memory.dmp

        memory/3120-135-0x00000000024D0000-0x00000000025A2000-memory.dmp

        memory/3580-144-0x0000000003250000-0x00000000032FE000-memory.dmp

        memory/3752-118-0x0000000000400000-0x0000000000537000-memory.dmp

        memory/3752-115-0x0000000000400000-0x0000000000537000-memory.dmp