TROJ_FAKEAV.WKA

Trend Micro has flagged this Trojan as noteworthy due to the increased potential for damage, propagation, or both, that it possesses. Specifically, it poses as a rogue antivirus software.

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

This Trojan connects to websites to download its component file, also detected as TROJ_FAKEAV.WKA. The aforementioned file then connects to remote sites to download another malicious component. Trend Micro also detects the component as this Trojan.

It then connects websites to display fake scanning result. It also connects to a remote site should the affected user chooses to purchase the full version of the fake rogue product.

This Trojan displays the following graphical user interface (GUI):

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.

Arrival Details

This Trojan may be downloaded from the following remote sites:

• http://{BLOCKED}ogle.info/tre/lena.exe/{random characters}

Autostart Technique

This Trojan adds the following registry entries to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
{random value} = %User Temp%\{random folder}\{random file name}.exe

Other System Modifications

This Trojan modifies the following registry key(s)/entry(ies) as part of its installation routine:

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Download
CheckExeSignatures = no

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings
ProxyEnable = 1

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

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Hardware Profiles\0001\Software\
Microsoft\windows\CurrentVersion\
Internet Settings
ProxyEnable = 1

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

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Hardware Profiles\Current\Software\
Microsoft\windows\CurrentVersion\
Internet Settings
ProxyEnable = 1

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

HKEY_CURRENT_CONFIG\Software\Microsoft\
windows\CurrentVersion\Internet Settings
ProxyEnable = 1

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

It adds the following registry keys as part of its installation routine:

HKEY_CURRENT_USER\Software\yr87fk3d2dnszapq2

It also creates the following registry entry(ies) as part of its installation routine:

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\PhishingFilter
EnabledV8 = 0

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\PhishingFilter
Enabled = 0

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Download
RunInvalidSignatures = 1

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings
ProxyServer = http={BLOCKED}.{BLOCKED}.0.1:8075

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings
ProxyOverride =

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Associations
LowRiskFileTypes = .exe

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Attachments
SaveZoneInformation = 1

Other Details

This Trojan does the following:

• Connects to any of the following websites to download its component file, which Trend Micro also detects as TROJ_FAKEAV.WKA:
  
  • http://{BLOCKED}ogle.info/tre/lena.exe/wHe46ed9e9V0100f060006R00000000102Ta9406b4e203L656e2d75730000000000
  • http://{BLOCKED}ogle.info/tre/lena.exe/xHe46ed9e9V0100f060006R00000000102Ta9406b42203l0409329
  • http://{BLOCKED}ogle.info/tre/lena.exe/yHe46ed9e9V0100f060006R00000000102Ta9406b42203l04093020
  The downloaded file is saved and executed as %System Root%\{random file name}.exe.

  The aforementioned file will then connect to the following remote sites to download another malicious component, also detected as TROJ_FAKEAV.WKA:

  • http://{BLOCKED}.192.250/user/xl3.php
  • http://{BLOCKED}.192.250/user/up/xl3.dat
  • http://{BLOCKED}ogle.info/tre/lena.exe/xHe46ed9e9V0100f060006R00000000102Ta9406b42203l0409328
  It then saves and executes the downloaded file as %User Temp%\{random folder}\{random file name}.exe.

• Connects to the following websites to display fake scanning result:
  
  • http://{BLOCKED}resh.com/check?pgid=8
  • http://{BLOCKED}resh.com/percer.php?login=ODMuMA==
  It displays the following graphical user interface (GUI):
  

  

  It also connects to the following remote site should the affected user chooses to purchase the full version of the fake rogue product:

  • http://{BLOCKED}resh.com/shop?abc=cGdpZD04JnI9ODMuMA==

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.