Win32/FakeScanti is a family of trojans that claim to scan for malware and display 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/FakeScanti variants have been observed to use names such as “Windows Antivirus Pro.”
Special Note:
Reports of
Rogue Antivirus programs have been more prevalent as of late. These are programs that generate misleading alerts and false detections in order to convince users to purchase illegitimate security software. Some of these programs may display product names or logos in an apparently unlawful attempt to impersonate Microsoft products.
Win32/FakeScanti is a family of trojans that claim to scan for malware and display 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/FakeScanti variants have been observed to use names such as “Windows Antivirus Pro.”
Installation
Win32/FakeScanti is typically downloaded and installed by another piece of malware, such as TrojanDownloader:Win32/FakeScanti. This downloads a self-extracting archive, saves it to a location such as %ProgramFiles%\Windows Antivirus Pro\ANTI_FILES.EXE, then launches this file to extract its contents to the same directory. The downloader then launches one of the extracted executables at %ProgramFiles%\Windows Antivirus Pro\Windows Antivirus Pro.exe to run the scanner.
Note that some of the extracted files include clean Microsoft DLLs which the malware requires in order to run.
The downloader also adds an item to the Programs Start menu, and a desktop shortcut such as the following:
Once the downloader has finished installing the malware, it deletes itself.
When first run Win32/FakeScanti extracts a number of files to the <system folder> (unless otherwise specified), with filenames such as the following:
-
desot.exe
-
dddesot.dll
-
%windir%\svchast.exe
-
onhelp.htm
It may periodically rewrite some of these files in an attempt to prevent them from being removed.
It also writes a self-extracting archive to a location such as %ProgramFiles%\Windows Antivirus Pro\tmp\dbsinit.exe. The contents of this are extracted and moved to the <system folder>\images directory. These consist of an HTML file and a number of image files which are used to render the malware’s fake Security Center window (see below). The HTML file and archive may be detected as Trojan:HTML\FakeScanti.
Payload
Displays fake antivirus scanner
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.
The following window is displayed after the completion of the scan:
Attempting to repair the files will result in the display of a dialogs such as the following:
The dialog below is displayed if scanning is interrupted:
If the user does not choose to activate the product, the following is displayed:
If the activation process is started, a page is displayed with the following banner:
Displays fake Windows Security Center
The malware periodically displays a window which is intended to resemble the Windows Security Center. Clicking any of the links in this window causes the fake scanner to be re-launched.
Prevents other executables from running
If the user attempts to run other applications, the malware attempts to prevent this from happening. It displays a message box with the following message: “The application has failed to start because the application configuration is incorrect. Reinstalling the application may fix this problem.”
Displays pop-ups
The malware may periodically display a popup balloon such as the following suggesting that the system is being attacked:
It may also display popup balloons from the system tray, such as the following:
Clicking on any of these causes the fake scanner to be re-launched.
It may also periodically display pop-ups such as the following:
Changes desktop background
At some time after it is first launched, the malware adds the following text to the user’s desktop background:
DANGER!!!
Your computer is INFECTED!
Attention!!!
Such infection will cause permanent loss of all information stored on your computer: documents, files, etc.
All your secret data like logins, passwords, credit card information can be accessed by third-parties for malicious purposes.
All your online activities like sending e-mails, visiting web-sites are logged and stored on your hard disk.
Spyware blocks the deletion of such information from your computer and makes your online actions traceable.
PROTECT YOURSELF!
DELETE SPYWARE FROM YOUR COMPUTER RIGHT NOW!
This is done by modifying a file at %AppData%\Microsoft\Internet Explorer\Desktop.htt, using the contents of files it earlier wrote to <system folder>\onhelp.htm and <system folder>\sonhelp.htm.
Displays fake error messages
The malware periodically displays the following dialog, which appears intended to resemble the Windows system error message:
If the user clicks the “Fix it” button, the fake scanner is re-launched. The other buttons do not appear to have any effect.
Reboots system
The malware occasionally reboots the system. This may be an attempt to convince the user that the system is infected with malware.
Blocks access to websites
Win32/FakeScanti may display the following pop-up and block access to websites that the user is attempting to visit. This dialog is displayed in order to convince the user that the site they are visiting is malicious and that they need to take a recommended action of the attacker's choice in order to be protected. Needless to say, this is false.
Analysis by David Wood
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.
To turn on the Windows Firewall in Windows Vista
-
Click Start, and click Control Panel.
-
Click Security.
-
Click Turn Windows Firewall on or off.
-
Select On.
-
Click OK.
To turn on the Internet Connection Firewall in Windows XP
-
Click Start, and click Control Panel.
-
Click Network and Internet Connections. If you do not see Network and Internet Connections, click Switch to Category View.
-
Click Change Windows Firewall Settings.
-
Select On.
-
Click OK.
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 websites.
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.
To turn on Automatic Updates in Windows Vista
-
Click Start, and click Control Panel.
-
Click System and Maintainance.
-
Click Windows Updates.
-
Select a setting. Microsoft recommends selecting Install updates automatically and choose a time that is convenient for you. If you do not choose Automatic, but you choose to be notified when updates are ready, a notification balloon appears when new downloads are available to install. Click the notification balloon to review and install the updates.
To turn on Automatic Updates in Windows XP
-
Click Start, and click Control Panel.
-
Click System.
-
Click Automatic Updates.
-
Select a setting. Microsoft recommends selecting Automatic. If you do not choose Automatic, but you choose to be notified when updates are ready, a notification balloon appears when new downloads are available to install. Click the notification balloon to review and install the updates.
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 that is updated with the latest signature files. Antivirus software is available from several sources. 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.
