TROJ_FAKEAV.WKA


 ALIASES:

Rogue:Win32/FakeSpypro (Microsoft)

 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

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.

  TECHNICAL DETAILS

File Size:

Varies

File Type:

PE

Memory Resident:

Yes

Initial Samples Received Date:

13 Jan 2011

Payload:

Downloads files, Displays windows

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.

  SOLUTION

Minimum Scan Engine:

8.900

VSAPI PATTERN File:

7.766.11

VSAPI PATTERN Date:

13 Jan 2011

VSAPI PATTERN Date:

1/13/2011 12:00:00 AM

VSAPI OPR PATTERN File:

7.767.00

VSAPI OPR PATTERN Date:

13 Jan 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.WKA

Step 3

Restart in Safe Mode

[ Learn More ]

Step 4

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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • {random value} = %User Temp%\{random folder}\{random file name}.exe
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\PhishingFilter
    • EnabledV8 = 0
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\PhishingFilter
    • Enabled = 0
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Download
    • RunInvalidSignatures = 1
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings
    • ProxyServer = http:\\{BLOCKED}.{BLOCKED}.0.1:8075
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings
    • ProxyOverride = <local>
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Associations
    • LowRiskFileTypes = .exe
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Attachments
    • SaveZoneInformation = 1

Step 5

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_CURRENT_USER\Software\Microsoft\Internet Explorer\Download
    • From: CheckExeSignatures = no
      To: yes
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings
    • From: ProxyEnable = 1
      To: 0
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Hardware Profiles\0001\Software\Microsoft\windows\CurrentVersion\Internet Settings
    • From: ProxyEnable = 1
      To: 0
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Hardware Profiles\Current\Software\Microsoft\windows\CurrentVersion\Internet Settings
    • From: ProxyEnable = 1
      To: 0
  • In HKEY_CURRENT_CONFIG\Software\Microsoft\windows\CurrentVersion\Internet Settings
    • From: ProxyEnable = 1
      To: 0

Step 6

Delete this registry key

[ 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. 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_CURRENT_USER\Software
    • yr87fk3d2dnszapq2

Step 7

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_FAKEAV.WKA. 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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