Analysis

  • max time kernel
    150s
  • max time network
    153s
  • platform
    windows7_x64
  • resource
    win7v20210410
  • submitted
    29/07/2021, 11:42

General

  • Target
    RA1_20210729.exe
  • Size 1.5MB
  • Sample210729-dxt3wh32js
  • SHA256 00d52b668be725580bf1233a8bc805f62831f96ca8f7cf50807cd3481727981a
  • MD5 SHA1 SHA512

Malware Config

Extracted

Family
  • remcos

Version
  • 3.1.5 Pro

Botnet
  • SA

C2
  • ego.ddns.net:2404

  • chasesure.duckdns.org:2404

Attributes
  • audio_folder

    MicRecords

  • audio_path

    %AppData%

  • audio_record_time

    5

  • connect_delay

    0

  • connect_interval

    1

  • copy_file

    rem.exe

  • copy_folder

    Remcos

  • delete_file

    false

  • hide_file

    false

  • hide_keylog_file

    false

  • install_flag

    true

  • install_path

    %AppData%

  • keylog_crypt

    false

  • keylog_file

    logs.dat

  • keylog_flag

    false

  • keylog_folder

    remcos

  • keylog_path

    %AppData%

  • mouse_option

    false

  • mutex

    Remcos-6KPFIK

  • screenshot_crypt

    false

  • screenshot_flag

    false

  • screenshot_folder

    Screenshots

  • screenshot_path

    %AppData%

  • screenshot_time

    10

  • startup_value

    Remcos

  • take_screenshot_option

    false

  • take_screenshot_time

    5

  • take_screenshot_title

    wikipedia;solitaire;

Signatures

  • Remcos

    Remcos is a closed-source remote control and surveillance software.

  • CustAttr .NET packer 1 IoCs

    Detects CustAttr .NET packer in memory.

  • Executes dropped EXE 2 IoCs
  • Loads dropped DLL 1 IoCs
  • Reads user/profile data of web browsers 2 TTPs

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

  • Adds Run key to start application 2 TTPs 4 IoCs
  • Suspicious use of SetThreadContext 2 IoCs
  • Enumerates physical storage devices 1 TTPs

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

  • Creates scheduled task(s) 1 TTPs 2 IoCs

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

  • Suspicious use of SetWindowsHookEx 1 IoCs
  • Suspicious use of WriteProcessMemory 46 IoCs

Processes

  • C:\Users\Admin\AppData\Local\Temp\RA1_20210729.exe
    "C:\Users\Admin\AppData\Local\Temp\RA1_20210729.exe"
    1⤵
    • Suspicious use of SetThreadContext
    • Suspicious use of WriteProcessMemory
    PID:768
    • C:\Windows\SysWOW64\schtasks.exe
      "C:\Windows\System32\schtasks.exe" /Create /TN "Updates\WfduhSfoZwnp" /XML "C:\Users\Admin\AppData\Local\Temp\tmpE705.tmp"
      2⤵
      • Creates scheduled task(s)
      PID:292
    • C:\Users\Admin\AppData\Local\Temp\RA1_20210729.exe
      "C:\Users\Admin\AppData\Local\Temp\RA1_20210729.exe"
      2⤵
      • Adds Run key to start application
      • Suspicious use of WriteProcessMemory
      PID:580
      • C:\Windows\SysWOW64\WScript.exe
        "C:\Windows\System32\WScript.exe" "C:\Users\Admin\AppData\Local\Temp\install.vbs"
        3⤵
        • Suspicious use of WriteProcessMemory
        PID:1184
        • C:\Windows\SysWOW64\cmd.exe
          "C:\Windows\System32\cmd.exe" /c "C:\Users\Admin\AppData\Roaming\Remcos\rem.exe"
          4⤵
          • Loads dropped DLL
          • Suspicious use of WriteProcessMemory
          PID:1572
          • C:\Users\Admin\AppData\Roaming\Remcos\rem.exe
            C:\Users\Admin\AppData\Roaming\Remcos\rem.exe
            5⤵
            • Executes dropped EXE
            • Suspicious use of SetThreadContext
            • Suspicious use of WriteProcessMemory
            PID:1220
            • C:\Windows\SysWOW64\schtasks.exe
              "C:\Windows\System32\schtasks.exe" /Create /TN "Updates\WfduhSfoZwnp" /XML "C:\Users\Admin\AppData\Local\Temp\tmpA238.tmp"
              6⤵
              • Creates scheduled task(s)
              PID:1608
            • C:\Users\Admin\AppData\Roaming\Remcos\rem.exe
              "C:\Users\Admin\AppData\Roaming\Remcos\rem.exe"
              6⤵
              • Executes dropped EXE
              • Adds Run key to start application
              • Suspicious use of SetWindowsHookEx
              PID:1628

Network

        MITRE ATT&CK Enterprise v6

        Replay Monitor

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        Downloads

        memory/580-69-0x0000000075EF1000-0x0000000075EF3000-memory.dmp

        memory/580-67-0x0000000000400000-0x0000000000479000-memory.dmp

        memory/580-71-0x0000000000400000-0x0000000000479000-memory.dmp

        memory/768-59-0x0000000001010000-0x0000000001011000-memory.dmp

        memory/768-62-0x00000000003B0000-0x00000000003BB000-memory.dmp

        memory/768-63-0x0000000005600000-0x00000000056CF000-memory.dmp

        memory/768-61-0x0000000004A70000-0x0000000004A71000-memory.dmp

        memory/768-64-0x0000000005320000-0x0000000005393000-memory.dmp

        memory/1220-79-0x0000000001050000-0x0000000001051000-memory.dmp

        memory/1220-81-0x00000000005F0000-0x00000000005F1000-memory.dmp

        memory/1628-91-0x0000000000400000-0x0000000000479000-memory.dmp