June 1, 2015
Macs older than a year are vulnerable to exploits that remotely overwrite the firmware that boots up the machine, a feat that allows attackers to control vulnerable devices from the very first instruction.
The attack, according to a blog post published Friday by well-known OS X security researcher Pedro Vilaca, affects Macs shipped prior to the middle of 2014 that are allowed to go into sleep mode. He found a way to reflash a Mac’s BIOS using functionality contained in userland, which is the part of an operating system where installed applications and drivers are executed. By exploiting vulnerabilities such as those regularly found in Safari and other Web browsers, attackers can install malicious firmware that survives hard drive reformatting and reinstallation of the operating system.