Tallies kept by the U.S. government’s computer security group show that Linux and Unix operating systems faced nearly three times the number of vulnerabilities in 2005 than did Microsoft’s often-maligned Windows. Although US-CERT didn’t break out Mac vulnerabilities in a separate category, the Linux/Unix section listed more than 25 attributed to the Apple Computer operating system. The end-of-year vulnerability score should be taken with a grain of salt, however, since US-CERT doesn’t filter out updates (so one actual vulnerability can be counted numerous times) nor does it break out individual vulnerabilities from warnings that cover multiple bugs (as in the many Mac OS X vulnerability listings).