Major Bash Vulnerability Affects Linux, UNIX, Mac OS X

A critical vulnerability in the Bourne again shell, simply known as Bash and which is present in most Linux and UNIX distributions and Apple’s Mac OS X, has been discovered and administrators are being urged to patch immediately.

The flaw allows an attacker to remotely attach a malicious executable to a variable that is executed when Bash is invoked. “It’s super simple and every version of Bash is vulnerable,” said Josh Bressers, manager of Red Hat product security. “It’s extremely serious, but you need very specific conditions in place where a remote user would be able to set that environment variable. Thankfully, it’s not common.”