WORM_SILLY.FSK

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.

It does not have any backdoor routine.

It does not have any downloading capability.

It does not have any information-stealing capability.

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 the following copies of itself into the affected system:

• %Application Data%\svchost.exe
• %Application Data%\lsass.exe
• %Application Data%\smss.exe
• %Windows%\inf\smss.exe
• %System%\Sexy Girls.scr

(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, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.. %Windows% is the Windows folder, which is usually C:\Windows.. %System% is the Windows system folder, which is usually C:\Windows\System32.)

Autostart Technique

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

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
FrameWorkService = "%Windows%\inf\smss.exe I'm so ugly, I hate myself and I want to die"

Other System Modifications

This worm adds the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer\DisallowRun

It adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer
DisallowRun = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer
NoFolderOptions = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer
NoRun = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer
NoFind = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer\DisallowRun
1 = "cmd.exe"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer\DisallowRun
2 = "mmc.exe"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer\DisallowRun
3 = "rstrui.exe"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer\DisallowRun
4 = "regedit.exe"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer\DisallowRun
5 = "regedt32.exe"

Propagation

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

• {Drive Letter}:\{User Name}_Fichiers.exe
• {Drive Letter}:\{folder name}\{folder name}.exe

Backdoor Routine

This worm does not have any backdoor routine.

Download Routine

This worm does not have any downloading capability.

Information Theft

This worm does not have any information-stealing capability.

NOTES:

This worm restricts the execution of the following files by adding specific registry entries:

• cmd.exe
• mmc.exe
• rstrui.exe
• regedit.exe
• regedt32.exe

It does not have rootkit capabilities.

It does not exploit any vulnerability.