TROJ_FAKEAV.BSM

This Trojan has increased potential for damage, propagation, or both, that it possesses. Specifically, it is related to an attack that involves blackhat SEO poisoning of Google Image search results.

To get a one-glance comprehensive view of the behavior of this Trojan, refer to the Threat Diagram shown below.

This Trojan poses as a legitimate antivirus software using various commercial names. Similar to other FAKEAV variants, TROJ_FAKEAV.BSM also displays several graphical users interfaces (GUIs) to users in an attempt to convince them of system infection and to purchase this purported cleaning software.

It gathers sensitive information from the user they choose to purchase the product. The information gathered includes credit card and contact details.

This Trojan may be downloaded by other malware/grayware from remote sites.

It employs registry shell spawning by adding certain registry entries. This allows this malware to execute even when other applications are opened.

It deletes itself after execution.

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.

File Size:

237,930 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

28 Apr 2011

Payload:

Drops files, Displays windows

Arrival Details

This Trojan may be downloaded by the following malware/grayware from remote sites:

http://{BLOCKED}tivirus.cz.cc/fast-scan

Installation

This Trojan drops the following non-malicious files:

C:\Documents and Settings\All Users\Application Data\{random file name}
%Application Data%\{random file name}
%User Profile%\Templates\{random file name}
%User Temp%\{random file name}

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

%Application Data%\{random file name}.exe

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

Autostart Technique

This Trojan employs registry shell spawning to ensure its execution when certain file types are accessed by adding the following entries:

HKEY_CLASSES_ROOT\.exe\shell\
open\command
(Default) = ""{malware path and file name}" -a "%1" %*"

HKEY_CLASSES_ROOT\exefile\shell\
open\command
(Default) = ""{malware path and file name}" -a "%1" %*"

HKEY_CURRENT_USER\Software\Classes\
.exe\shell\open\
command
(Default) = ""{malware path and file name}" -a "%1" %*"

HKEY_CURRENT_USER\Software\Classes\
exefile\shell\open\
command
(Default) = ""{malware path and file name}" -a "%1" %*"

Other System Modifications

This Trojan adds the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\DomainProfile
EnableFirewall = "0"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\DomainProfile
DoNotAllowExceptions = "0"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\DomainProfile
DisableNotifications = "1"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile
EnableFirewall = "0"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile
DoNotAllowExceptions = "0"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile
DisableNotifications = "1"

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Clients\
StartMenuInternet\FIREFOX.EXE\shell\
open\command
(Default) = ""{malware path and file name}" -a "%Program Files%\Mozilla Firefox\firefox.exe""

(Note: The default value data of the said registry entry is %Program Files%\Mozilla Firefox\firefox.exe.)

HKEY_LOCAL_MACHINE\SOFTWARE\Clients\
StartMenuInternet\FIREFOX.EXE\shell\
safemode\command
(Default) = ""{malware path and file name}" -a "%Program Files%\Mozilla Firefox\firefox.exe" -safe-mode"

(Note: The default value data of the said registry entry is "%Program Files%\Mozilla Firefox\firefox.exe" -safe-mode.)

HKEY_LOCAL_MACHINE\SOFTWARE\Clients\
StartMenuInternet\IEXPLORE.EXE\shell\
open\command
(Default) = ""{malware path and file name}" -a "%Program Files%\Internet Explorer\iexplore.exe""

(Note: The default value data of the said registry entry is "%Program Files%\Internet Explorer\iexplore.exe".)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
AntiVirusDisableNotify = "1"