TROJ_FAKEAV.DAC
Windows 2000, Windows XP, WindowsServer 2003
Threat Type: Trojan
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
This Trojan modifies registry entries to disable the Windows Firewall settings. This action allows this malware to perform its routines without being deteted by the Windows Firewall.
It executes the files it drops, prompting the affected system to exhibit the malicious routines they contain.
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
339,968 bytes
EXE
No
05 Apr 2011
Displays message/message boxes, Drops files
Installation
This Trojan drops the following copies of itself into the affected system:
- %User Profile%\Local Settings\Application Data\{random three letter}.exe
(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.)
It drops the following files:
- %system root%\Documents and Settings\All Users\Application Data\3ucghnxb07i7cm6irx618633uore80rii22kfxm8k1w3b7
- %User Profile%\Local Settings\Application Data\3ucghnxb07i7cm6irx618633uore80rii22kfxm8k1w3b7
- %User Temp%\3ucghnxb07i7cm6irx618633uore80rii22kfxm8k1w3b7
- %User Profile%\Templates\3ucghnxb07i7cm6irx618633uore80rii22kfxm8k1w3b7
(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.. %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, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.)
Other System Modifications
This Trojan adds the following registry entries as part of its installation routine:
HKEY_CLASSES_ROOT\.exe\shell\
open\command
@ = "%User Profile%\Local Settings\Application Data\{random three letter}.exee" -a "%1" %*
HKEY_CURRENT_USER\Software\Classes\
.exe\shell\open\
command
@ = "%User Profile%\Local Settings\Application Data\{random three letter}.exe" -a "%1" %*
HKEY_CURRENT_USER\Software\Classes\
exefile\shell\open\
command
@ = "%User Profile%\Local Settings\Application Data\{random three letter}.exee" -a "%1" %*
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
AntiVirusDisableNotify = 1
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
AntiVirusOverride = 1
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
FirewallDisableNotify = 1
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
FirewallOverride = 1
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
UpdatesDisableNotify = 1
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
It modifies the following registry key(s)/entry(ies) as part of its installation routine:
HKEY_CLASSES_ROOT\exefile\shell\
open\command
@ = "%User Profile%\Local Settings\Application Data\{random three letter}.exe" -a "%1" %*
(Note: The default value data of the said registry entry is "%1" %*.)
HKEY_LOCAL_MACHINE\SOFTWARE\Clients\
StartMenuInternet\IEXPLORE.EXE\shell\
open\command
@ = "%User Profile%\Local Settings\Application Data\{random three letter}.exe" -a "%Program Files%\Internet Explorer\iexplore.exe"
(Note: The default value data of the said registry entry is "%Program Files%\Internet Explorer\iexplore.exe".)
It modifies the following registry entries to disable the Windows Firewall settings:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile
EnableFirewall = 0
(Note: The default value data of the said registry entry is 1.)
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile
DisableNotifications = 1
(Note: The default value data of the said registry entry is 0.)
Dropping Routine
This Trojan executes the files it drops, prompting the affected system to exhibit the malicious routines they contain.
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.
SOLUTION
8.900
7.952.01
05 Apr 2011
Step 1
Delete this registry value
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_CLASSES_ROOT\.exe\shell\open\command
- @ = %User Profile%\Local Settings\Application Data\{random three letter}.exee -a %1 %*
- @ = %User Profile%\Local Settings\Application Data\{random three letter}.exe -a %1 %*
- @ = %User Profile%\Local Settings\Application Data\{random three letter}.exee -a %1 %*
- AntiVirusDisableNotify = 1
- AntiVirusOverride = 1
- FirewallDisableNotify = 1
- FirewallOverride = 1
- UpdatesDisableNotify = 1
- EnableFirewall = 0
- DoNotAllowExceptions = 0
- DisableNotifications = 1
Step 2
Restore this modified registry value
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_CLASSES_ROOT\exefile\shell\open\command
- @ = %User Profile%\Local Settings\Application Data\{random three letter}.exe -a %1 %*
- @ = %1 %*
- In HKEY_LOCAL_MACHINE\SOFTWARE\Clients\StartMenuInternet\IEXPLORE.EXE\shell\open\command
- @ = %User Profile%\Local Settings\Application Data\{random three letter}.exe -a %Program Files%\Internet Explorer\iexplore.exe
- @ = %Program Files%\Internet Explorer\iexplore.exe
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile
- EnableFirewall = 0
- EnableFirewall = 1
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile
- DisableNotifications = 1
- DisableNotifications = 0
Step 3
Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.
Step 4
Scan your computer with your Trend Micro product to delete files detected as TROJ_FAKEAV.DAC. 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.
Step 5
Search and delete this file
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