WORM_AUTORUN.BKG

This worm 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 uses the default Windows folder icon to trick users into opening the file. Double-clicking the file executes this malware.

It drops copies of itself in removable drives. These dropped copies use the names of the folders located on the said drives for their file names. It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

However, as of this writing, the said sites are inaccessible.

Arrival Details

This worm 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.

Installation

This worm drops the following non-malicious files:

• %System%\{random characters}\cnvpe.fne
• %System%\{random characters}\dp1.fne
• %System%\{random characters}\eAPI.fne
• %System%\{random characters}\HtmlView.fne
• %System%\{random characters}\internet.fne
• %System%\{random characters}\krnln.fnr
• %System%\{random characters}\RegEx.fnr
• %System%\{random characters}\shell.fne
• %System%\{random characters}\spec.fne
• %User Temp%\E_N4\cnvpe.fne
• %User Temp%\E_N4\dp1.fne
• %User Temp%\E_N4\eAPI.fne
• %User Temp%\E_N4\HtmlView.fne
• %User Temp%\E_N4\internet.fne
• %User Temp%\E_N4\krnln.fnr
• %User Temp%\E_N4\shell.fne
• %User Temp%\E_N4\spec.fne

(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.. %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003.)

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

• %System%\{random characters}\{Random characters}.exe

(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)

It creates the following folders:

• %System%\{random characters}
• %User Temp%\E_N4

(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.. %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003.)

It uses the default Windows folder icon to trick users into opening the file. Double-clicking the file executes this malware.

Autostart Technique

This worm drops the following shortcut pointing to its copy in the User Startup folder to enable its automatic execution at every system startup:

• {malware file name}.lnk

Propagation

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

• Recycle.exe

It drops copies of itself in removable drives. These dropped copies use the names of the folders located on the said drives for their file names.

It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

The said .INF file contains the following strings:

[AutoRun]
open=Recycle.exe
shell\1={random characters}
shell\1\Command=Recycle.exe
shell\2\={random characters}
shell\2\Command=Recycle.exe
shellexecute=Recycle.exe

Other Details

This worm connects to the following possibly malicious URL:

• www.{BLOCKED}.{BLOCKED}n.com

However, as of this writing, the said sites are inaccessible.