BleepingComputer.com: Trojan.byteverify virus, Help appreciated

Norton keeps picking this up in my idle full system scan, it says it is fully removed but then it finds it the next time as well. I have only ran Malewarebytes and that came up clear. My computer seems a little slower and lags a little but no other noticeable differences, yet. Any advice on what to do?

Java.ByteVerify is a method to exploit a security vulnerability in the Microsoft Virtual Machine that is stored in the java cache as a java-applet. The vulnerability arises as the ByteCode verifier in the Microsoft VM does not correctly check for the presence of certain malformed code when a java-applet is loaded. Attackers can exploit the vulnerability by creating malicious Java applets and inserting them into web pages that could be hosted on a web site or sent to users as an attachment. Trojan Exploit ByteVerify indicates that a Java applet - a malicious Java archive file (JAR) - was found on your system containing the exploit code.

When a browser runs an applet, the Java Runtime Environment (JRE) stores the downloaded files into its cache folder (C:\Documents and Settings\username\Application Data\Sun\Java\Deployment\cache) for quick execution later and better performance. Malicious applets are also stored in the Java cache directory and your anti-virus may detect them and provide alerts. Notification of these files as a threat does not always mean that a machine has been infected; it indicates that a program included the viral class file but this does not mean that it used the malicious functionality.

These malicious applets are designed to exploit vulnerabilities in the Microsoft VM (Microsoft Security Bulletin MS03-011). If you are using the Sun JVM as your default virtual machine, these malicious applets cannot cause any harm to your computer. For more specific information about Java exploits, please refer to Virus found in the Java cache directory.

A number of anti-virus programs (AVG, avast, CA, Kaspersky, Symantec) and scanners will detect Java/ByteVerify (Exploit.OSX.Smid.c, Java:Djewers) but they cannot remove the applets. If you have the Java-Plugin installed, then deleting them from the Java cache should eliminate the problem. The Java Plug-In in the Control Panel is only present if you are using Sun's Java. If you don't have the Java-Plugin installed then just delete the files manually. The Microsoft Virtual machine stores the applets in the Temporary Internet Files.

Clear the entire cache to ensure everything is cleaned out:

• Clear the Java cache
  
• Clear the browser cache in Internet Explorer
  
• Safely Delete the Temporary Internet Files <- for Internet Explorer 8
  
• How to Clear Your Browser's Cache <- for other versions of Internet Explorer, Firefox and different browsers
  
• Clean out Windows temporary files

Also be aware that older versions of Java have vulnerabilities that malicious sites can use to exploit and infect your system. That's why it is important to always use the most current Java Version and remove outdated Java components.

• Microsoft: ‘Unprecedented Wave of Java Exploitation’
  
• Drive-by Trojan preying on out-of-date Java installations
  
• Ghosts of Java Haunt Users
  
• Hole in Patch Process

Even Java advises users to always have the latest version of the Java since it contains security updates and improvements to previous versions.

Quote

Why should I upgrade to the latest Java version?
Why should I upgrade to Java 6?

You can verify (test) your JAVA Software Installation & Version here.