WORM_NUQEL.VXE

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

Arrival Details

This worm 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 worm drops a copy of itself in the following folders using different file names:

• %Windows%\regsvr.exe
• %System%\regsvr.exe
• %System%\svchost.exe

(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.. %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

It creates the following folders with attributes set to System and Hidden to prevent users from discovering and removing its components:

• %System%\28463
• %Temporary Internet Files%\Virtualized
• %Application Data%\Microsoft\Windows\Privacl\Low
• %Application Data%\Microsoft\Windows\IECompatCache\Low
• %Application Data%\Microsoft\Windows\IETIdCache\Low

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.. %Temporary Internet Files% is the Temporary Internet Files folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temporary Internet Files on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Microsoft\Windows\Temporary Internet Files on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), and Windows Server 2008; C:\Users\{user name}\AppData\Local\Microsoft\Windows\INetCache on Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), and Windows Server 2012.. %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.)

Autostart Technique

This worm modifies the following registry entries to ensure it automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
Msn Messenger = "%System%\regsvr.exe"

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows NT\CurrentVersion\Winlogon
shell = "Explorer.exe regsvr.exe"

Download Routine

This worm accesses the following websites to download files:

• www.yahoo.com/{BLOCKED}g.doc

Other Details

This worm sets the attributes of the following file(s) to Hidden and System:

• %System%\regsvr.exe
• %System%\svchost.exe
• %System%\setup.ini
• %System%\setting.ini

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

It drops the following file(s)/component(s):

• %System%\setting.ini
• %System%\setup.ini

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)