Cardown.B is a Java applet based trojan that downloads and installs Startpage.Y trojan on the system.
Cardown activates when user views a web page or HTML email that contains reference to the trojan file.
Cardown does not replicate and does not infect the host system, the only operations it does is to modify Interner Explorer start page and download and install Startpage.Y trojan component.
Update you Internet Explorer using Windows update to prevent any further infections.
1. Open https://windowsupdate.microsoft.com
2. Select all available updates
3. Windows update installs updates and reboots
4. Return to the Windows updates to make sure you have all updated
Clear the Internet Explorer temporary file cache
1. Open Internet Explorer
2. Select "Tools"->"Internet Options..." from the top menu
3. Select "General" tab (this should be visible already)
4. Click from "Temporary Internet files" pane button "Delete Files..."
5. Select checkbox "Delete all offline content"
6. Click "OK"
Scan your computer with F-Secure Anti-Virus to remove any other downloaded components.
A False Positive is when a file is incorrectly detected as harmful, usually because its code or behavior resembles known harmful programs. A False Positive will usually be fixed in a subsequent database update without any action needed on your part. If you wish, you may also:
Check for the latest database updates
First check if your F-Secure security program is using the latest updates, then try scanning the file again.
Submit a sample
After checking, if you still believe the file is incorrectly detected, you can submit a sample of it for re-analysis.
Note: If the file was moved to quarantine, you need to collect the file from quarantine before you can submit it.
Exclude a file from further scanning
If you are certain that the file is safe and want to continue using it, you can exclude it from further scanning by the F-Secure security product.
Note: You need administrative rights to change the settings.
The Cardown.B is activated when a web site containing the trojan is loaded with unpacthed Microsoft Internet Explorer browser. When the JAR file containing the trojan is executed it uses Microsoft Internet Explorer VerifierBug vulnerability to get full privileges by escaping the Java security, and execute its code.
When executed the trojan modifies the Internet Explorer start page to point to the site where the trojan is downloaded from.
In addition to changing the Internet Explorer settings the trojan downloads trojan downloader win32.StartPage.Y and executes it.