Backdoor.Win32.REMCOS.TICOGCE

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

It executes commands from a remote malicious user, effectively compromising the affected system.

Arrival Details

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

Installation

This Backdoor drops the following files:

• %User Temp%\install.vbs ->-> deletes the original malware file and executes the copy
• %Application Data%\remcos\logs.dat -> contains the information stolen from the victim

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).. %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

It drops the following copies of itself into the affected system:

• %Application Data%\System32\task.exe

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

It adds the following processes:

• {Malware path and Malware name}
• %System%\WSCript.exe" "%User Temp%\install.vbs"
• %Application Data%\System32\task.exe

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).. %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

It creates the following folders:

• %Application Data%\System32\
• %Application Data%\remcos

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

It adds the following mutexes to ensure that only one of its copies runs at any one time:

• Mutex_RemWatchdog
• Remcos_Mutex_Inj

Autostart Technique

This Backdoor adds the following registry entries to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
task = %Application Data%\System32\task.exe

Backdoor Routine

This Backdoor executes the following commands from a remote malicious user:

• Create, Enumerate, Modify and Delete Registry Keys and Values
• Create, Enumerate, Modify, Start, Stop and Delete Services
• Create Image
• Change Wallpaper
• Start or Stop Keylogger (Activities is logged in logs.dat)
• Restart, Sleep, Logs off or Shutdown affected Computer
• Copy clipboard data
• Set clipboard data
• Clear clipboard data
• Download file/s to affected computer
• Upload file/s from affected computer
• Delete file/s
• Rename file/s
• Enumerate Files
• Enumerate Process
• Terminate Process
• Download file
• Screen Capture
• Create Directory
• Delete Directory
• Change File attributes
• Play, Pause, Stop and Record Audio
• Show, Open, Maximize, Minimize and Exit/Close a Window
• Execute File
• Save Image
• Enumerates and Checks Open Window
• Pop-up a Menu or a Message Box
• Retrieve and Clear logins and login credentials and cookies from the following browsers:
  • Google Chrome
  • Mozilla Firefox
  • Internet Explorer

It connects to the following URL(s) to send and receive commands from a remote malicious user:

• {BLOCKED}-169-192.{BLOCKED}hosting.com

As of this writing, the said sites are inaccessible.

Information Theft

This Backdoor gathers the following data:

• Computer Name
• Windows Architecture (x32 or x64)
• User Privilage (Admin or Not)
• Username
• Locale Info
• Keyboard Input
• Mouse Activity
• User Keystrokes
• User Activity (Idle Time)
• Memory Information
• Enumerate Drives and Get Drive type

Other Details

This Backdoor adds the following registry keys:

HKEY_CURRENT_USER\Software\Remcos-F5NWKC
exepath = {Hex Values}

HKEY_CURRENT_USER\Software\Remcos-F5NWKC
licence = {Hex Values}

HKEY_CURRENT_USER\Software\Local AppWizard-Generated Applications

HKEY_CURRENT_USER\Software\Local AppWizard-Generated Applications\
{File Name}

HKEY_CURRENT_USER\Software\Local AppWizard-Generated Applications\
{File Name}\Recent File List

HKEY_CURRENT_USER\Software\Local AppWizard-Generated Applications\
{File Name}\Settings