WORM_SILLY.XGH

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

It displays pop-up advertisements when ActiveX is enabled.

Installation

This worm drops the following copies of itself into the affected system:

• %User Profile%\csrss.exe

(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.)

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
Taskman = %User Profile%\csrss.exe

It adds and runs the following services:

• a

Propagation

This worm creates the following folders in all removable drives:

• {drive letter}\MUSKO

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

• {drive letter}\MUSKO\karikatura.exe

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

It modifies the contents of an existing AUTORUN.INF file to automatically execute its dropped copy. It does this by adding the following strings in the .INF file:

• [autorun
• {garbage characters}
• open=MUSKO///karikatura.exe
• {garbage characters}
• icon=%SystemRoot%\system32\SHELL32.dll,4
• {garbage characters}
• action=Open folder to view files using Windows Explorer
• {garbage characters}
• Shell\open\command=MUSKO///karikatura.exe
• {garbage characters}
• shell\open\command=MUSKO///karikatura.exe
• {garbage characters}
• USEAUTOPLAY=1
• {garbage characters}

Adware Routine

This worm displays pop-up advertisements when ActiveX is enabled.