Apple says 'Shellshock' no risk to vast majority of Mac users

Apple Inc (AAPL.O) said the vast majority of Mac computer users are not at risk from the recently identified "Shellshock" computer bug, which security experts have warned affect operating systems, including Mac's OS X.

"The vast majority of OS X users are not at risk," Apple spokesman Bill Evans said late Thursday evening.

"Shellshock" is a vulnerability in Bash, a piece of software packaged with Mac OS X, which is based on the Unix operating system. The bug does not appear to affect Apple's iOS, which is used on the iPhone and iPad, or machines running Microsoft Corp's (MSFT.O) Windows software.

Security experts disclosed the "Shellshock" vulnerability in Bash on Wednesday, saying that it could enable attackers to gain remote control of vulnerable systems.

Apple ships its computers so they are "safe by default," Evans said, which means that they are not vulnerable to remote attacks unless users configure them for "advanced" Unix services.

"We are working to quickly provide a software update for our advanced UNIX users," he said.

The computer industry is rushing to determine which systems can be remotely compromised by hackers, but there are currently no estimates on the number of vulnerable systems.