Earlier this week, Apple released updates for OS X and iOS, incorporating a raft of security patches. (What is the correct collective noun for patches anyway? A quilt?)
Amongst the fixes were a patch for the boobytrapped message that mischief-makers could send to your iPhone to cause it to crash. So, if you didn't find the idea of your friends and enemies remotely restarting your phone funny, you had best update to iOS 8.4.
But it wasn't just mobile users who were benefiting from improvements by Apple's security team.
Desktop and laptop users of OS X are advised to either update to OS X Yosemite v10.10.4, or apply Security Update 2015-005, which incorporate numerous security fixes, including patches for remote code execution flaws, elevation of privilege vulnerabilities, browser data leakages and security bypasses.
But alongside the fixes is another security update — for your Mac or MacBook's firmware — that provides important protection against a serious vulnerability that could allow an attacker to meddle with the system BIOS, installing a rootkit which would lead to your computer being permanently backdoored.
The so-called "Prince Harming" attack was similar to the Thunderstrike vulnerability patched earlier this year in OS X 10.10.2, but was considered more serious because, unlike Thunderstrike, it did not depend upon a hacker having physical access to the intended victim's computer.
OS X security researcher Pedro Vilaça detailed how the "Prince Harming" attack was able to exploit Mac computers made before mid-2014, exploiting the fact that their low-level firmware was left vulnerable to attack when woken from sleep mode.
According to Vilaça, sophisticated attackers had a window of opportunity to inject malicious rootkit code into the ROM EFI boot chip. The attack could even be delivered remotely by exploiting browser vulnerabilities and tricking intended victims into visiting a boobytrapped webpages. Provided the victim's computer had entered sleep mode during the current cycle, it could be exploited.
That's bad enough, but now consider just what a rootkit can do.
A rootkit can control your entire computer from the first second that it's turned on, running at such a low level that it can completely backdoor your system — logging every keypress, spying on your every activity, stealing and bypassing firmware passwords.
And, once in place, a malicious rootkit could easily go undetected for a long long time.
Frankly, the attack was likely to be beyond the capabilities of the typical attacker because of its sophistication (a financially-motivated hacker, for instance, would probably be happy to steal cash or identities in a more conventional and easy fashion), but there is no doubt that it is a technique that would be of interest to determined hackers — such as those working for intelligence agencies and foreign governments.
Regardless of your chances of being hit, it's still good that Apple has now patched this security vulnerability — and a similar one known as "Dark Jedi."
Vilaça, who went public with details of the Prince Harming vulnerability affecting ROM EFI boot chips earlier this year in the belief that Apple already knew about the problem, praised a fix being finally issued for older computers:
"I am very happy to see that Apple moved fast enough to fix both bugs and must congratulate them. It was a bit unexpected! Maybe full disclosure and bad publicity work after all ;-)."
If you haven't already done so, apply Mac EFI Security Update 2015-001, and update to OS X Yosemite v10.10.4.