Apple's decision to deprecate Java may have an upside: If Java does disappear from the Mac, a lot of potential security problems go away.

One such problem surfaced on Wednesday, albeit a relatively minor one. Mac security company Intego reported that it had discovered a Mac OS X version of the Koobface malware, which is designed to spread on social networks like Facebook, MySpace, and Twitter.

The malware is actually able to attack multiple platforms, but it targets Mac OS X though a malicious Java applet.

Earlier this month, Microsoft reported "an unprecedented wave of Java exploitation," a consequence of the fact that Java installations are often not up-to-date.

Intego says that users may encounter the Mac Koobface malware through links on social networks or other Web sites. The links lead to video Web sites that attempt to load the malicious Java applet. This will trigger the standard Mac OS X Java security alert dialog box.

"Users can deny or allow the applet access to their computers," Intego explains in its security advisory. "If they click Deny, the applet will not run, and no infection will occur. If they click Allow, however, the applet will run, and will attempt to download files from one or more remote servers."

Files that are downloaded will be stored in a hidden directory. They include components necessary to attack Mac OS X, Linux, and Windows. In theory, the Mac OS X version of Koobface is as dangerous as the Windows version. It's designed to create a local Web server and IRC server as a means of participating in a botnet, to change the user's DNS settings, and to incorporate other functions provided through subsequent downloads.

But Intego says that the Mac malware is not as dangerous as it might be because it's poorly coded.

"While this is an especially malicious piece of malware, the current Mac OS X implementation is flawed, and the threat is therefore low," Intego says. "However, Mac users should be aware that this threat exists, and that it is likely to be operative in the future, so this Koobface Trojan horse may become an issue for Macs."

Security software companies have been saying as much for years.