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Win32/Yektel


Win32/Yektel is a family of trojans that display fake warnings of spyware or malware in an attempt to lure the user into installing or paying money to register rogue security products such as Trojan:Win32/FakeXPA. It is downloaded by most variants of Win32/FakeXPA.


What to do now

Manual removal is not recommended for this threat. To detect and remove this threat and other malicious software that may have been installed, run a full-system scan with an up-to-date antivirus product such as Microsoft Security Essentials, or the Microsoft Safety Scanner. For more information about using antivirus software, see http://www.microsoft.com/security/antivirus/av.aspx.

Threat behavior

Win32/Yektel is a family of trojans that display fake warnings of spyware or malware in an attempt to lure the user into installing or paying money to register rogue security products such as Trojan:Win32/FakeXPA. It is downloaded by most variants of Win32/FakeXPA.
Installation
Each Win32/Yektel variant consists of an EXE (TrojanDownloader:Win32/Yektel) which downloads and installs a DLL (Trojan:Win32/Yektel) as a BHO (Browser Helper Object).
 
TrojanDownloader:Win32/Yektel usually copies itself to one or both of these file names:
 
  • <system folder>\explorer32.exe
  • <system folder>\ieupdates.exe
 
It modifies the registry to execute one of these copies each time Windows starts, e.g.:
 
Adds value: "ieupdates"
With data: "<system folder>\ieupdates.exe"
To subkey: HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
 
Or:
 
Adds value: "ieupdate"
With data: "<system folder>\explorer32.exe "
To subkey: HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
 
The downloader usually saves Trojan:Win32/Yektel.A as:
<system folder>\winsrc.dll
 
This DLL is installed as a BHO by setting registry entries such as these:
 
Creates key: HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Browser Helper Objects\{037C7B8A-151A-49E6-BAED-CC05FCB50328}
 
Sets value: (default)
With data: "<system folder>\winsrc.dll"
In subkey: HKCR\CLSID\{037C7B8A-151A-49E6-BAED-CC05FCB50328}\InprocServer32
 
Sets value: (default)
With data: "&Research"
In subkey: HKCR\CLSID\{037C7B8A-151A-49E6-BAED-CC05FCB50328}
Payload
Displays Misleading Messages
Win32/Yektel displays warnings and recommendations in Internet Explorer. These include messages that appear at the top of the Internet Explorer window, mimicking IE drop-down messages:
 
 
The above appears on top of web pages that the user visits. The trojan may also display a fake warning page instead of a requested web page:
 
Yektel fake IE warning page
 
The above messages are displayed at random times while browsing. A third type of message is added into all web pages retrieved from any URL containing the string “google”:
 
Yektel fake Google recommendation
 
Clicking on any of the links in any of these messages usually leads to web site that encourages the user to pay money to register a rogue security product such as Win32/FakeXPA.
 
Win32/Yektel will not display fake warning messages when the user visits any domains from a list stored inside the trojan, such as:
 
antivirus2009online.com
antivirus-2009pro.com
antivirus2009-software.com
antivirusa2.com
antivirusa2.com
antivirus-database.com
antivirusprotection2009.com
billingserviceonline.com
browsersecuritycenter.com
eticketsclub.com
extrabilling.com
fileshredder2008.com
fileshreddersoftware.com
innovagest2000sl.com
internetscannerlive.com
myantivirusprotection2009.com
pandora-software.com
psbill.com
purchase-anti.com
purchase-soft.com
secure.billingware.net
secure.extrabilling.com
secure.innovagest.2000sl.com
securetds-a5.com
software-payment.com
stock-flow.com
trafficrotator.net
update-direct.com
updateserver6.com
woodpckr-a2.com
woodpckr-a2.com
woodst-sale.com
xp-antivirus.com
xpantivirussecurity.com
xpprotectionsoftware.com
 
Analysis by Hamish O'Dea

Symptoms

System Changes
The following system changes may indicate the presence of this malware:
  • The presence of the following files:
    <system folder>\explorer32.exe
    <system folder>\ieupdates.exe
    <system folder>\winsrc.dll
  • The presence of the following registry modifications (for example):
    Adds value: "ieupdates"
  • With data: "<system folder>\ieupdates.exe"
    To subkey: HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
     
    Adds value: "ieupdate"
    With data: "<system folder>\explorer32.exe "
    To subkey: HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    Sets value: (default)
    With data: "<system folder>\winsrc.dll"
    In subkey: HKCR\CLSID\{037C7B8A-151A-49E6-BAED-CC05FCB50328}\InprocServer32
     
    Sets value: (default)
    With data: "&Research"
    In subkey: HKCR\CLSID\{037C7B8A-151A-49E6-BAED-CC05FCB50328}
  • The display of the following messages, or similar:



Prevention

Take the following steps to help prevent infection on your system:
  • Enable a firewall on your computer.
  • Get the latest computer updates for all your installed software.
  • Use up-to-date antivirus software.
  • Use caution when opening attachments and accepting file transfers.
  • Use caution when clicking on links to Web pages.
  • Avoid downloading pirated software.
  • Protect yourself against social engineering attacks.
  • Use strong passwords.
Enable a firewall on your computer
Use a third-party firewall product or turn on the Microsoft Windows Internet Connection Firewall.
Get the latest computer updates
Updates help protect your computer from viruses, worms, and other threats as they are discovered. It is important to install updates for all the software that is installed in your computer. These are usually available from vendor Web sites.
 
You can use the Automatic Updates feature in Windows to automatically download future Microsoft security updates while your computer is on and connected to the Internet.
Use up-to-date antivirus software
Most antivirus software can detect and prevent infection by known malicious software. To help protect you from infection, you should always run antivirus software, such as Microsoft Security Essentials, that is updated with the latest signature files. For more information, see http://www.microsoft.com/protect/computer/viruses/vista.mspx.
Use caution when opening attachments and accepting file transfers
Exercise caution with e-mail and attachments received from unknown sources, or received unexpectedly from known sources.  Use extreme caution when accepting file transfers from known or unknown sources.
Use caution when clicking on links to Web pages
Exercise caution with links to Web pages that you receive from unknown sources, especially if the links are to a Web page that you are not familiar with, unsure of the destination of, or suspicious of. Malicious software may be installed in your system simply by visiting a Web page with harmful content.
Avoid downloading pirated software
Threats may also be bundled with software and files that are available for download on various torrent sites. Downloading "cracked" or "pirated" software from these sites carries not only the risk of being infected with malware, but is also illegal. For more information, see 'The risks of obtaining and using pirated software'.
Protect yourself from social engineering attacks
While attackers may attempt to exploit vulnerabilities in hardware or software in order to compromise a system, they also attempt to exploit vulnerabilities in human behavior in order to do the same. When an attacker attempts to take advantage of human behavior in order to persuade the affected user to perform an action of the attacker's choice, it is known as 'social engineering'. Essentially, social engineering is an attack against the human interface of the targeted system. For more information, see 'What is social engineering?'.
Use strong passwords
Attackers may try to gain access to your Windows account by guessing your password. It is therefore important that you use a strong password – one that cannot be easily guessed by an attacker. A strong password is one that has at least 8 characters, and combines letters, numbers, and symbols. For more information, see http://www.microsoft.com/protect/yourself/password/create.mspx.

Alert level: Severe
This entry was first published on: Dec 09, 2008
This entry was updated on: Apr 17, 2011

This threat is also detected as:
No known aliases