Cardown.A 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 download and install Startpage.Y trojan component.
To remove Cardown.A from your system:
Find the latest advice in our Community Knowledge Base.
See the manual for your F-Secure product on the Help Center.
Submit a file or URL for further analysis.
Cardown is a Java applet that is heavily obfuscated and uses scrambling in it's strings. The trojan is not packaged in to a Jar file so each component class file is individually loaded when trojan executes, so in most cases the user will get a warning about the first component file and will not receive the rest of the malware.
When the trojan is executed it uses Microsoft Internet Explorer VerifierBug vulnerability to get full privileges by escaping the Java security, and execute its code. Then the trojan downloads bootconf.exe into Windows directory (default C:\Windows) and modifies registry so that the trojan starts automatically at Windows startup.
Further information about the vulnerability in the Microsoft Java VM, including a fix, is available at: https://www.microsoft.com/technet/security/bulletin/ms03-011.asp
The trojan makes following registry changes:
Added registry keys:
Removed registry keys: