All computers with Java installed need to be updated to the current version as soon as possible. Macintoshes are being infected at a rapid rate by a malicious program called Flashback, which exploits recent Java vulnerabilities via malicious websites. Mac users should update using Apple's Software Update as soon as possible. Windows computers are also vulnerable to a variety of malicious programs that take advantage of out-of-date Java plugins. Windows users should update to the most recent Java by visiting the Java site. Mac users who run MacOS 10.5.x (Leopard) or earlier, be advised that your Mac will no longer be receiving updates. Java should be turned off entirely in that case. It's also a good idea to take this time to be sure all of your browser plugins are up to date. In addition to keeping browser plugins up to date, leave them turned off unless actually planning to use them on a given site.