Threat Encyclopedia

TROJ_FAKEAV.ZZJ

Malware type: Trojan

Aliases: No Alias Found

In the wild: Yes

Destructive: No

Language: English

Platform: Windows 98, ME, NT, 2000, XP, Server 2003

Encrypted: No

Overall risk rating:

Reported infections:

Damage potential:

Medium

Distribution potential:

Low

Description: 

A Trojan horse program is a malware that is not capable of automatically spreading to other systems. Trojans are usually downloaded from the Internet and installed by unsuspecting users.

Trojans typically carry payloads or other malicious actions that can range from the mildly annoying to the irreparably destructive. They may also modify system settings to automatically start. Restoring affected systems may require procedures other than scanning with an antivirus program.

For additional information about this threat, see:

Description created: Mar. 21, 2010 12:05:35 PM GMT -0800


TECHNICAL DETAILS


File type: PE

Memory resident:  Yes

Size of malware: 199,168 Bytes

Initial samples received on: Mar 17, 2010

Details:

Installation and Autostart Technique

This Trojan drops the following copy of itself:

  • %Application Data%\ave.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.)

It drops the following non-malicious files:

  • %Application Data%\GDIPFONTCACHEV1.DAT - contains font information
  • %Application Data%\NGjnR - encrypted component
  • %System Root%\Document and Settings\All Users\Application Data\NGjnR - encrypted component

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located. )

It terminates the initially executed copy and executes the dropped copy.

This Trojan registers itself as a system service to ensure its automatic execution at every system startup. It does this by creating the following registry keys/entries:

HKEY_CLASSES_ROOT\secfile
(Default) = "Application"
Content Type = "application/x-msdownload"

HKEY_CLASSES_ROOT\secfile\DefaultIcon
(Default) = "%1"

HKEY_CLASSES_ROOT\secfile\shell\open\command
(Default) = "%Application Data%\ave.exe" /START "%1" %*"
IsolatedCommand = ""%1" %*"

HKEY_CLASSES_ROOT\secfile\shell\runas\command
(Default) = ""%1" %*"
IsolatedCommand = ""%1" %*"

HKEY_CLASSES_ROOT\secfile\shell\start\command
(Default) = ""%1" %*"
IsolatedCommand = ""%1" %*"

HKEY_CLASSES_ROOT\.exe\DefaultIcon
(Default) = "%1"

HKEY_CLASSES_ROOT\.exe\shell\open\command
(Default) = ""%Application Data%\ave.exe" /START "%1" %*"
IsolatedCommand = ""%1" %*"

HKEY_CLASSES_ROOT\.exe\shell\runas\command
(Default) = ""%1" %*"
IsolatedCommand = ""%1" %*"

HKEY_CLASSES_ROOT\.exe\shell\start\command
(Default) = ""%1" %*"
IsolatedCommand = ""%1" %*"

HKEY_CURRENT_USER\Software\Microsoft\GDIPlus
FontCachePath = "%Application Data%"

Other System Modifications

It creates the following registry key/entry as part of its installation routine:

HKEY_CURRENT_USER\Software\Microsoft\Windows
Identity = {values}

It creates the following registry keys/entries to bypass Windows firewall:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\
SharedAccess\Parameters\FirewallPolicy\DomainProfile
EnableFirewall = "0"
DoNotAllowExceptions = "0"
DisableNotifications = "1"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\
SharedAccess\Parameters\FirewallPolicy\StandardProfile
EnableFirewall ="0"
DoNotAllowExceptions = "0"
DisableNotifications "1"

Other Details

Upon execution, it displays the following fake alerts:

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 Web site asking for sensitive information, such as credit card numbers.

Analysis By: Roland Dela Paz

Revision History:

First pattern file version: 8.168.09
First pattern file release date: May 20, 2011

SOLUTION


Minimum scan engine version needed: 8.900

Pattern file needed: 8.169.00

Pattern release date: May 20, 2011


Important note: The "Minimum scan engine" refers to the earliest Trend Micro scan engine version guaranteed to detect this threat. However, Trend Micro strongly recommends that you update to the latest version in order to get comprehensive protection. Download the latest scan engine here.

Solution:

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

 Step 1:  Delete this registry key  [learn how]

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. Before you could do this, you must restart in Safe Mode. For instructions on how to do this, you may refer to this page If the preceding step requires you to restart in safe mode, you may proceed to edit the system registry.

  • In HKEY_CLASSES_ROOT\.exe
    • DefaultIcon
  • In HKEY_CLASSES_ROOT\.exe\shell
    • runas
    • start
  • In HKEY_CLASSES_ROOT
    • secfile
  • In HKEY_CURRENT_USER\Software\Microsoft
    • GDIPlus

 Step 2:  Delete this registry value  [learn how]

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_CURRENT_USER\Software\Microsoft\
    Windows
    • Identity = "{values}"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
    Services\SharedAccess\Parameters\
    FirewallPolicy\DomainProfile
    • DoNotAllowExceptions = "0"
    • EnableFirewall = "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
    • DisableNotifications = "1"
    • DoNotAllowExceptions = "0"
    • EnableFirewall = "0"

 Step 3: Search and delete these files  [learn how]

*Note: There may be some component files that are hidden. Please make sure you uncheck Hide protected operating system files in Folders Option>View tab, and then 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.

  • %Application Data%\GDIPFONTCACHEV1.DAT - contains font information
  • %Application Data%\NGjnR - encrypted component
  • %System Root%\Document and Settings\All Users\Application Data\NGjnR - encrypted component

 Step 4: Scan your computer with your Trend Micro product to delete files detected as TROJ_FAKEAV.ZZJ  

*Note: 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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