WORM_WERVIK.H

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

It deletes registry entries, causing some applications and programs to not function properly.

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

It connects to certain websites to send and receive information. It deletes the initially executed copy of itself. It gathers information and reports it to its servers.

Arrival Details

This Trojan arrives via removable drives.

It may arrive via network shares.

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

This malware arrives via the following means:

• Executing the infected RAR file that contains a copy of the malware

Installation

This Trojan drops the following files:

• %Application Data%\svchost.exe.ini - contains USB availability status
• %User Temp%\time.txt - contains system date
• {Drive Letter}:\autoexec.bat - will be used in propagation via RAR files
• {Drive Letter}:\system.bin - will be used in propagation via RAR files
• %User Temp%\rar.dat - will be used in propagation via RAR files

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

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

• %Application Data%\svchost.exe
• %User Temp%\readme.exe

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

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

• appdatasvchost.exe

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
svchost.exe = "%Application Data%\svchost.exe"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
svchost.exe = "%Application Data%\svchost.exe"

It drops the following file(s) in the Windows User Startup folder to enable its automatic execution at every system startup:

• %User Startup%\svchost.exe

(Note: %User Startup% is the current user's Startup folder, which is usually C:\Documents and Settings\{user}\Start Menu\Programs\Startup on Windows 2000 and XP, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows Vista, 7, and 8.)

Other System Modifications

This Trojan deletes the following files:

• %User Temp%\{filename}.vbs
• %User Startup%\{filename}.vbs
• %Application Data%\{filename}.vbs
• {Drive Letter}:\{filename}.vbs
• {Drive Letter}:\{filename}.scr
• {Drive Letter}:\{filename}.lnk

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

It adds the following registry keys:

HKEY_CURRENT_USER\Software\name

It adds the following registry entries:

HKEY_CURRENT_USER\Software\name
name = "baqa_{Volume Serial Number}"

It deletes the following registry entries:

HKEY_CLASSES_ROOT\lnkfile
IsShortcut = ""

Propagation

This Trojan creates the following folders in all removable drives:

• {Removable Drive Letter}:\My Pictures
• {Removable Drive Letter}:\My Documents
• {Removable Drive Letter}:\Games

It drops copies of itself in network drives such as the following:

• {Drive Letter}:\{malware filename}.exe

It drops the following copy(ies) of itself in all removable drives:

• {Removable Drive Letter}:\My Pictures\svchost.exe
• {Removable Drive Letter}:\My Documents\svchost.exe
• {Removable Drive Letter}:\Games\svchost.exe

Backdoor Routine

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

• Collect information about the computer
• Download file
• Execute file
• Uninstall itself
• Restart the computer
• Perform denial of service attacks
• Start Internet Explorer
• Display a message box
• Send Facebook messages
• Send Skype messages
• Display advertisements

Process Termination

This Trojan terminates the following processes if found running in the affected system's memory:

• wscript.exe

Other Details

This Trojan connects to the following website to send and receive information:

• {BLOCKED}to.{BLOCKED}o.org

It does the following:

• It exits if it detects it is running in a Virtual Machine or Sandbox environment.
• It searches for .rar files and inserts itself to the RAR container as:
  
  • readme.exe
  
  
• It creates a Windows Firewall exception using the following command:
  
  • firewall add allowedprogram "%Application Data%\svchost.exe" "svchost.exe" ENABLE

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

It deletes the initially executed copy of itself

It gathers the following information and reports it to its servers:

• contents of created registry entry: name = "baqa_{Volume Serial Number}"
• Operating System
• Computer Name
• User Name
• USB availability status
• Installed .NET Framework
• Installed Anti-Virus
• Installed Firewall
• System Date
• Window Title

NOTES:

It does not have rootkit capabilities.

It does not exploit any vulnerability.