Ransom.Win32.RHYSIDA.YXDGTT

It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Recopila determinada información del equipo afectado.

Detalles de entrada

It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Instalación

Agrega los procesos siguientes:

• %System%\cmd.exe /c cmd.exe /c vssadmin.exe Delete Shadows /All /Quiet
• %System%\cmd.exe /c cmd.exe /c for /F "tokens=*" %1 in ('wevtutil.exe el') DO wevtutil.exe cl "%1"
• %System%\cmd.exe /c cmd.exe /c start powershell.exe -WindowStyle Hidden -Command "Sleep -Milliseconds 1000; schtasks /end /tn Rhsd; schtasks /delete /tn Rhsd /f; schtasks /create /sc ONSTART /tn Rhsd /tr \"'{Malware File Path}\{Malware File Name}.exe' {accepted arguments}\" /ru system; schtasks /run /tn Rhsd /i
• %System%\cmd.exe /c cmd.exe /c start powershell.exe -WindowStyle Hidden -Command \"Sleep -Milliseconds 1000; schtasks /delete /tn Rhsd /f
• %System%\cmd.exe /c cmd.exe /c start ping 127.0.0.1 -n 2 > nul && del /f /q "{Malware File Path}\{Malware File Name}.exe"
• %System%\cmd.exe /c cmd.exe /c reg delete \"HKCU\Contol Panel\Desktop\" /v Wallpaper /f
• %System%\cmd.exe /c cmd.exe /c reg delete \"HKCU\Conttol Panel\Desktop\" /v WallpaperStyle /f
• %System%\cmd.exe /c cmd.exe /c reg add \"HKCU\Software\Microsoft\Windows\CurrentVersion\Policies\ActiveDesktop\" /v NoChangingWallPaper /t REG_SZ /d 1 /f
• %System%\cmd.exe /c cmd.exe /c reg add \"HKLM\Software\Microsoft\Windows\CurrentVersion\Policies\ActiveDesktop\" /v NoChangingWallPaper /t REG_SZ /d 1 /f
• %System%\cmd.exe /c cmd.exe /c reg add \"HKCU\Control Panel\Desktop\" /v Wallpaper /t REG_SZ /d \"%Public%\bg.jpg\" /f
• %System%\cmd.exe /c cmd.exe /c reg add \"HKLM\Software\Microsoft\Windows\CurrentVersion\Policies\System\" /v Wallpaper /t REG_SZ /d \"%Public%\bg.jpg\" /f
• %System%\cmd.exe /c cmd.exe /c reg add \"HKLM\Software\Microsoft\Windows\CurrentVersion\Policies\System\" /v WallpaperStyle /t REG_SZ /d 2 /f
• %System%\cmd.exe /c cmd.exe /c reg add \"HKCU\Control Panel\Desktop\" /v WallpaperStyle /t REG_SZ /d 2 /f
• %System%\cmd.exe /c rundll32.exe user32.dll,UpdatePerUserSystemParameters

(Nota: %System% es la carpeta del sistema de Windows, que en el caso de Windows 98 y ME suele estar en C:\Windows\System, en el caso de Windows NT y 2000 en C:\WINNT\System32 y en el caso de Windows 2000(32-bit), XP, Server 2003(32-bit), Vista, 7, 8, 8.1, 2008(64-bit), 2012(64bit) y 10(64-bit) en C:\Windows\System32).

Otras modificaciones del sistema

Cambia el fondo de escritorio mediante la modificación de las siguientes entradas de registro:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
ActiveDesktop
NoChangingWallPaper = 1

(Note: The default value data of the said registry entry is 0.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Policies\
ActiveDesktop
NoChangingWallPaper = 1

(Note: The default value data of the said registry entry is 0.)

HKEY_CURRENT_USER\Control Panel\Desktop
Wallpaper = %Public%\bg.jpg

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Policies\
System
Wallpaper = %Public%\bg.jpg

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Policies\
System
WallpaperStyle = 2

(Note: The default value data of the said registry entry is 0.)

HKEY_CURRENT_USER\Control Panel\Desktop
WallpaperStyle = 2

(Note: The default value data of the said registry entry is 0.)

Este malware establece la imagen siguiente como fondo de escritorio del sistema:

• %Public%\bg.jpg
  

Robo de información

Recopila la siguiente información del equipo afectado:

• Number of processors
• System information

Acepta los siguientes parámetros:

• -d {path to encrypt} → used to specify directory to encrypt
• -sr → used to remove/delete itself if -S is not passed as an argument
• -nobg → avoids replacing desktop wallpaper and avoids disabling the ability to replace desktop wallpaper
• -md5
• -S → avoids ransomware routine and creates scheduled task named Rhsd to execute itself on system startup

Otros detalles

Agrega las siguientes entradas de registro como parte de la rutina de instalación:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies
ActiveDesktop =

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Policies
ActiveDesktop =

Hace lo siguiente:

• It changes the desktop wallpaper after encryption and prevents the user from changing it back by modifying the NoChangingWallpaper registry value.
• It uses wevtutil.exe to clear Windows event logs.
• It initializes resources based on the number of processors available in the system.
• It encrypts all available drives from A to Z.