Security Tool is a variant of Win32/Winwebsec - a family of programs that claims to scan for malware and displays fake warnings of “malicious programs and viruses”. They then inform the user that they need to pay money to register the software in order to remove these non-existent threats.
Win32/Winwebsec has been distributed with many different names. The name used by the malware, the user interface and other details vary to reflect each variant’s individual branding. The following details describe Win32/Winwebsec when it is distributed with the name Security Tool.
When distributed as Security Tool, Win32/Winwebsec creates a directory under %COMMON_APPDATA% or %APPDATA% with a randomly generated name (for example, C:\Documents and Settings\All Users\Application Data\65124927). The fake scanner is copied to this folder, using the same name as that of the folder (for example "65124927.exe" or "gcutvzlen.exe").
The registry is modified to ensure that the fake scanner is executed at each Windows start:
Adds value: "<randomly generated>" (same as the fake scanner file name, for example 65124927)
With data: "<path to rogue>" (for example, C:\Documents and Settings\All Users\Application Data\65124927\65124927.exe)
To subkey: HKLM\SOFTWARE\MICROSOFT\WINDOWS\CURRENTVERSION\RUN
It also creates the following shortcuts to the rogue executable on the desktop and under Start | Programs:
• %DESKTOPDIRECTORY%\Security Tool.lnk
• %PROGRAMS%\Security Tool.lnk
Win32/Winwebsec displays the following message box after finishing its installation:
Displays false/misleading malware alerts
When run, the malware performs a fake scan of the system, and falsely claims that a number of files on the system are infected with malware. Should users request that it clean the reported infections, it advises them that they need to pay money to register the program in order for it to do so.
Please see below for examples of interface, fake alerts, false scanning results, and pop-ups used by Win32/Winwebsec when distributed as Security Tool:
The malware also checks if the Internet Explorer or Mozilla Firefox web browsers are running on the system by monitoring any open window with the following class names:
If found, the malware displays a false Firewall message indicating that it has blocked the browser from accessing the Internet, as shown below:
After installation, and upon each subsequent re-boot of the system, Security Tool prevents the user from launching any application by terminating its process and displaying a message that falsely claims that the process is infected. For instance, if calc.exe is launched, the malware displays the following dialog:
Win32/Winwebsec, however, avoids terminating the following processes:
Modifies system settings
Trojan:Win32/Winwebsec hides all icons on the desktop, as well as removing the affected system's default desktop wallpaper by making the following registry modification
Removes value: "Wallpaper"
From subkey: HKCU\Control Panel\Desktop
Analysis by Amir Fouda
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
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