Java is increasingly the focus of both malware developers and security researchers. Many malware packages include Java code, and drive-by malware infections often use known Java vulnerabilities to trigger web browser-based infections. Java releases are filled with fixes for security vulnerabilities. Security researchers find new Java holes with alarming frequency.
Many Windows computers also contain the Java Runtime Environment (JRE), which allows standalone Java applications to run without a web browser. Many system administration tools are developed in Java, since this allows the same code to run on many different operating systems. There are also plenty of Java games, including the hugely popular Minecraft. Although Minecraft can be run from within a web browser, the full version of the game runs in the JRE.
Java vulnerabilities exist both in Java browser plugins and in the JRE. However, Java code that runs in the JRE must be explicitly downloaded and installed by the user. For example, to play the full version of Minecraft, the user must go to the Minecraft web site, buy the game, download the installer, install the game on their computer, then run the game. On the other hand, Java code on a malicious or hacked web site can run automatically and invisibly the moment a user visits that web site – if their browser has a functioning Java plugin.
Clearly, Java web browser plugins present a much greater security risk than standalone Java. Our recommendations – echoed by the ARS Technica article – remain the same: you should seriously consider disabling Java plugins in your web browser, but it’s okay to leave the JRE installed on your computer.