Update: Apple has issued a statement to iMore regarding this issue, stating that most Mac users are already protected unless they have configured “advanced UNIX services.” An update is in the works to protect those users.
A vulnerability in Bash, the software used to control the command shell in many flavors of Unix, has been shown to be present in OS X – with some security researchers saying that the flaw could pose a bigger threat than the Heartbleed vulnerabilty discovered last year (which affected many Unix systems but not OS X).
The Bash vulnerability being referred to by some as ‘Shell Shock’ allows an attacker to run a wide range of malicious code remotely. It was discovered by security researchers at RedHat, and is described in detail in a blog post.
There are conflicting reports as to the extent to which Mac users are at risk … expand full story