WORM_FAKEAV.BSF

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 connects to certain URLs. It may do this to remotely inform a malicious user of its installation. It may also do this to download possibly malicious files onto the computer, which puts the computer at a greater risk of infection by other threats.

It displays fake alerts that warn users of infection. It also displays fake scanning results of the affected system. It then asks for users to purchase it once scanning is completed. If users decide to purchase the rogue product, users are directed to a certain website asking for sensitive information, such as credit card numbers.

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 non-malicious files:

• %User Profile%\Application Data\ANSAV_AIO\ANSAV.ini
• %User Temp%\cconfig.anv
• %User Temp%\config.anv
• %User Temp%\dbs.anv
• %User Temp%\main.log

(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.. %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:

• %User Profile%\Application Data\ANSAV_AIO\ansavgl.exe
• %User Profile%\Application Data\ANSAV_AIO\ ANSAV.exe
• %User Temp%\ANSAV.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.. %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 creates the following folders:

• %User Profile%\Application Data\ANSAV_AIO

(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\CurrentVersion\Run
An Software Lab = "%User Profile%\Application Data\ANSAV_AIO\ansavgl.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
Ansav Guard = "%User Profile%\Application Data\ANSAV_AIO\ ANSAV.exe"

Download Routine

This worm connects to the following malicious URLs:

• http://{BLOCKED}te.ansav.com

Rogue Antivirus Routine

This worm displays fake alerts that warn users of infection. It also displays fake scanning results of the affected system. It then asks for users to purchase it once scanning is completed. If users decide to purchase the rogue product, users are directed to a certain website asking for sensitive information, such as credit card numbers.

NOTES:

It creates the following folders in physical, removable and network drives:

• ANSAV_AIO
• ANSAV_AIO\Plugins

It drops copies of itself in the said drives as the following files:

• ANSAV_AIO\agd32.sys
• ANSAV_AIO\anPdetector.dll
• ANSAV_AIO\ANSAV.exe
• ANSAV_AIO\arc.dll
• ANSAV_AIO\fixer.fx
• ANSAV_AIO\Plugins\DeepSlayer.dll
• ANSAV_AIO\Plugins\HiddenRevealer.dll
• ANSAV_AIO\Plugins\MalTrack.dll
• ANSAV_AIO\Plugins\Process Image Finder.dll
• ANSAV_AIO\Plugins\RegistryFX.dll
• ANSAV_AIO\Plugins\xscript.dll
• ANSAV_AIO\ste.dll
• ANSAV_AIO\vdb