News is breaking about a massive vulnerability in Intel CPUs -- a vulnerability that could potentially allow hackers to gain access to protected system memory holding encryption keys, authentication details and other goodies. Happy New Year.
Normally, each process running on an Intel CPU has its own address space. The system has an address space separate from all of the process address spaces. In normal operation, processes may be able to see parts of the kernel address space to complete necessary operations, but they can't change data in the kernel space. And the ability for a process to see into the kernel space is carefully controlled for both security and system stability reasons.
Because of the flaw, first recognized by a research group from Graz University of Technology, Austria, obliquely discussed in a paper titled KASLR is DEAD: Long Live KASLR, [Author's Note: KASLR is Kernel Address Space Layout Randomization, a technique that increases security by frequently moving kernel addresses around.] the separation between the user (process) space and kernel space can become very porous. And then it gets worse.
Modern Intel CPUs boost performance by trying to anticipate what processes will need, essentially pre-executing commands to make data available as quickly as possible. By carefully manipulating these commands executed ahead of time, a hacker can gain access to the contents of kernel memory that they shouldn't be allowed to see. And then it gets worse.
The first step down the path toward "worse" is ubiquity: It doesn't matter which operating system you're using -- it's going to have to be patched in order to deal with this vulnerability. This is the rare case in which Linux users can't be smug, nor can MacOS users or Windows users. And those who keep their systems rigorously updated are no safer than those still running a decade-old system. In the words of REM, "Everybody hurts."
Now, there's a glimmer of good news, in that the OS can be patched to shut off the technology that leads to the vulnerability, but that medicine comes with a foul side-effect: Your patched systems will be slower. How much slower? Depending on precisely which applications and processes you're running, anywhere from 20% to 33% slower. Let that sink in for a moment.
The only people who don't have to worry at all about this vulnerability are those running systems powered by AMD processors, because they do things differently when it comes to memory page table isolation and speculative operations/data references. Of course, AMD processors have had their own security issues in the past, so those system owners should probably be a bit circumspect in their gloating.
For those keeping score, this vulnerability exploit is similar in many ways to the rowhammer bug used to gain access to the contents of DRAM. It's likely that we will see more of these hardware-based exploits as operating system and application programmers get better at testing and correcting flaws before they hit general availability.
This story is going to continue to develop, so stay tuned to us here at Security Now. And let us know if you hear any news about this flaw, especially if you hear reliable information on exploits beyond the current proof-of-concept attacks seen so far.
Welcome to 2018 and fasten your seatbelts -- it's going to be a rocky year.
— Curtis Franklin is the editor of SecurityNow.com. Follow him on Twitter @kg4gwa.