TROJ_FAKEAV.BSK

 Analysis by: kathleenno

 ALIASES:

Trojan.FakeAV!gen54 (Symantec); Rogue:Win32/FakeRean (Microsoft); FakeAlert-Rena.f (Mcafee); Mal/FakeAV-FS (Sophos)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

This malware installs itself on the infected system as a rogue antivirus application using certain names that include the affected system's Operating System (OS).

Should the user choose to purchase the rogue product, it gathers the confidential information.

This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious 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.

  TECHNICAL DETAILS

File Size:

234,051 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

16 May 2011

Payload:

Compromises system security, Displays message/message boxes, Connects to URLs/IPs, Drops files, Modifies system registry

Arrival Details

This Trojan 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 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

(Note: The default value data of the said registry entry is 0.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
FirewallDisableNotify = 1

(Note: The default value data of the said registry entry is 0.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
UpdatesDisableNotify = 1

(Note: The default value data of the said registry entry is 0.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
AntiVirusOverride = 1

(Note: The default value data of the said registry entry is 0.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
FirewallOverride = 1

(Note: The default value data of the said registry entry is 0.)

Other Details

This Trojan deletes itself after execution.

Rogue Antivirus Routine

This Trojan 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 may install itself on the infected system as a rogue antivirus using the following names:

  • {OS Name} Anti-Spyware
  • {OS Name} Anti-Spyware 2011
  • {OS Name} Anti-Virus 2011
  • {OS Name} Home Security
  • {OS Name} Home Security 2011
  • {OS Name} Internet Security 2011
  • {OS Name} Security 2011
  • {OS Name} Total Security
  • {OS Name} Total Security 2011
It displays the following graphical user interface (GUI):
If users decide to purchase the rogue product, they are then directed to any of following sites asking for sensitive information, such as credit card numbers:
  • {BLOCKED}suk.com
  • {BLOCKED}zikagec.com
  • {BLOCKED}bojine.com
  • {BLOCKED}wytyg.com
  • {BLOCKED}sob.com
  • {BLOCKED}nuworyr.com
  • {BLOCKED}zuz.com
  • {BLOCKED}zedap.com
  • {BLOCKED}lap.com
  • {BLOCKED}culypod.com
  • {BLOCKED}satipa.com
  • {BLOCKED}xukyk.com
  • {BLOCKED}gap.com
  • {BLOCKED}cobeqevi.com
  • {BLOCKED}cawezawe.com
  • {BLOCKED}wuzejuk.com
  • {BLOCKED}tikicare.com
  • {BLOCKED}sys.com
  • {BLOCKED}lexut.com
  • {BLOCKED}sofem.com
  • {BLOCKED}hyt.com
  • {BLOCKED}qej.com
  • {BLOCKED}ruseqoda.com
  • {BLOCKED}lot.com
  • {BLOCKED}tatev.com
  • {BLOCKED}wemyvuda.com
  • {BLOCKED}vymuzi.com
  • {BLOCKED}canyvi.com
  • {BLOCKED}piweso.com
  • {BLOCKED}pihune.com
  • {BLOCKED}vokizax.com
  • {BLOCKED}furosup.com
  • {BLOCKED}geced.com
  • {BLOCKED}vulot.com
  • {BLOCKED}xosomov.com
  • {BLOCKED}zegito.com
  • {BLOCKED}jil.com
  • {BLOCKED}ozenaj.com
  • {BLOCKED}lymucy.com
  • {BLOCKED}navygu.com
  • {BLOCKED}vydor.com
  • {BLOCKED}hinynuh.com
  • {BLOCKED}pomike.com
  • {BLOCKED}luj.com
  • {BLOCKED}gulerewy.com
  • {BLOCKED}.com
  • {BLOCKED}gevuryt.com
  • {BLOCKED}lyr.com
  • {BLOCKED}mugoto.com
  • {BLOCKED}susefim.com
  • {BLOCKED}rus.com
  • {BLOCKED}nuhy.com
  • {BLOCKED}duq.com
  • {BLOCKED}sex.com
  • {BLOCKED}kyf.com
  • {BLOCKED}kub.com
  • {BLOCKED}pih.com
  • {BLOCKED}zinuhe.com
  • {BLOCKED}papavi.com
  • {BLOCKED}nazo.com
  • {BLOCKED}dububy.com
  • {BLOCKED}fyp.com
  • {BLOCKED}rydup.com
  • {BLOCKED}zupilog.com
  • {BLOCKED}gol.com
  • {BLOCKED}femu.com
  • {BLOCKED}syde.com
  • {BLOCKED}jybi.com
  • {BLOCKED}qimysu.com
  • {BLOCKED}himal.com
  • {BLOCKED}juvax.com
  • {BLOCKED}jab.com
  • {BLOCKED}puhaz.com
  • {BLOCKED}keke.com
  • {BLOCKED}.com
  • {BLOCKED}pyzoqah.com
  • {BLOCKED}gacotate.com
  • {BLOCKED}hesikyv.com
  • {BLOCKED}gyduloj.com
  • {BLOCKED}wyt.com
  • {BLOCKED}bijahiw.com
  • {BLOCKED}sunupi.com
  • {BLOCKED}sivude.com
  • {BLOCKED}zenaj.com
  • {BLOCKED}sahysese.com
  • {BLOCKED}sutecyd.com
  • {BLOCKED}semijawo.com
  • {BLOCKED}zyref.com
  • {BLOCKED}jywyrade.com
  • {BLOCKED}zom.com
  • {BLOCKED}byv.com
  • {BLOCKED}syfage.com
  • {BLOCKED}gac.com
It may gather the following information if the user chooses to activate the product:
  • Credit card information (i.e. card type, card number, expiration date, security code)
  • Contact information (i.e. name, address, email, phone number)

  SOLUTION

Minimum Scan Engine:

8.900

FIRST VSAPI PATTERN FILE:

8.160.09

FIRST VSAPI PATTERN DATE:

16 May 2011

Step 1

For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.

Step 2

Scan your computer with your Trend Micro product and note files detected as TROJ_FAKEAV.BSK

Step 3

Restart in Safe Mode

[ Learn More ]

Step 4

Restore this modified registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer"s registry.

HKEY_CLASSES_ROOT\.exe\shell\open\command
HKEY_CLASSES_ROOT\exefile\shell\open\command
HKEY_CURRENT_USER\Software\Classes\.exe\shell\open\command
HKEY_CURRENT_USER\Software\Classes\exefile\shell\open\command

Step 5

Delete this registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\DomainProfile
    • EnableFirewall = 0
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\DomainProfile
    • DoNotAllowExceptions = 0
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\DomainProfile
    • DisableNotifications = 1
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile
    • EnableFirewall = 0
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile
    • DoNotAllowExceptions = 0
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile
    • DisableNotifications = 1

Step 6

Restore this modified registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\SOFTWARE\Clients\StartMenuInternet\FIREFOX.EXE\shell\open\command
    • From: (Default) = {malware path and file name} -a %Program Files%\Mozilla Firefox\firefox.exe
      To: %Program Files%\Mozilla Firefox\firefox.exe
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Clients\StartMenuInternet\FIREFOX.EXE\shell\safemode\command
    • From: (Default) = {malware path and file name} -a %Program Files%\Mozilla Firefox\firefox.exe -safe-mode
      To: %Program Files%\Mozilla Firefox\firefox.exe -safe-mode
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Clients\StartMenuInternet\IEXPLORE.EXE\shell\open\command
    • From: (Default) = {malware path and file name} -a %Program Files%\Internet Explorer\iexplore.exe
      To: %Program Files%\Internet Explorer\iexplore.exe
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
    • From: AntiVirusDisableNotify = 1
      To: 0
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
    • From: FirewallDisableNotify = 1
      To: 0
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
    • From: UpdatesDisableNotify = 1
      To: 0
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
    • From: AntiVirusOverride = 1
      To: 0
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
    • From: FirewallOverride = 1
      To: 0

Step 7

Search and delete this file

[ Learn More ]
There may be some component files that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden files and folders in the search result.  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}

Step 8

Scan your computer with your Trend Micro product to delete files detected as TROJ_FAKEAV.BSK. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.


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