It has been pretty difficult to avoid the news of Meltdown and Spectre – Two vulnerabilities recently discovered that could potentially be exploited to gain access to sensitive information on PCs, Macs, servers, and smartphones. Meltdown and Spectre affect virtually all devices that contain CPUs, which amounts to billions of devices worldwide.
What are Meltdown and Spectre?
Meltdown and Spectre are two separate vulnerabilities affecting CPUs – central processing units. The chips that power a wide range of electronic devices. The flaws make devices vulnerable to side-channel attacks, in which it is possible to extract information from instructions that have been run on CPUs, using the CPU cache as a side channel.
There are three types of attacks, two for Spectre and one for Meltdown. Spectre Variant 1 – tracked as CVE-2017-5753- is a bounds check bypass, while Spectre variant 2 – tracked as CVE-2017-5715 – is a branch target injection. Variant 3, termed Meltdown – tracked as CVE-2017-5754 – is a rogue data cache load, memory access permission check that is performed after kernel memory read.
The less technical explanation is the attacks leverage the prediction capabilities of the CPU. The CPU will predict processes, load them to an easily accessible, fast sector of the memory to save time and ensure fast performance. Spectre allows data to be read from the memory, but also for information to be loaded into the memory and read that would otherwise not be possible.
Meltdown also reads information from the memory, stealing information from memory used by the kernel that would not normally be possible.
What Devices are Affected by Meltdown and Spectre?
US-CERT has warned that the following vendors have been affected by Meltdown and Spectre: AMD, Apple, Arm, Google, Intel, Linux Kernel, Microsoft, and Mozilla. Apple has said that virtually all of its Macs, iPhones, and iPads are affected. PCs and laptops with Intel, Arm, and AMD chips are affected by Spectre, as are Android smartphones. while Meltdown affects desktops, laptops, and servers with Intel chips. Since servers are affected, that has major implications for cloud service providers.
How Serious are Meltdown and Spectre?
How serious are Meltdown and Spectre? Serious enough for the Intel chief executive officer, Brian Krzanich, to sell $25 million of his shares in the company prior to the announcement of the flaws, although he maintains there was no impropriety and the sale of the shares was unrelated to the announcement of the flaws a little over a month later.
For users of virtually all devices that contain CPUs, the flaws are certainly serious. They could potentially be exploited by malicious actors to gain access to highly sensitive data stored in the memory, which can include passwords and credit card data.
What makes these flaws especially serious is the number of devices that are affected – billions of devices. Since one of the flaws affects the hardware itself, which cannot be easily corrected without a redesign of the chips, resolving the problem will take a considerable amount of time. Some security experts have predicted it could take decades before the flaws are totally eradicated.
At present, it would appear that the flaws have not been exploited in the wild, although now the news has broken, there will certainly be no shortage of individuals attempting to exploit the flaws. Whether they are able to do so remains to be seen.
What Can You do to Prevent Meltdown and Spectre Attacks?
As is the case when any vulnerability is identified, protecting against Meltdown and Spectre requires patches to be applied. All software should be updated to the latest versions, including operating systems, software packages, and browsers. Keeping your systems 100% up to date is the best protection against these and other attacks.
Some third-party antivirus software will prevent Windows patches from being installed, so before Windows can be updated, antivirus must be updated. Ensure that your AV program is kept up to date, and if you have automatic updates configured for Windows, as soon as your system is ready for the update it will be installed.
Chrome and Firefox have already been updated, Microsoft will be rolling out a patch for Windows 10 on Thursday, and over the next few days, updates will be released for Windows 7 and 8. Apple has already updated MacOS version 10.13.2, with earlier versions due to receive an update soon.
Google has already issued updates for Android phones, although only Google devices have so far been updated, with other manufactures due to roll out the updates shortly. Google has already updates its Cloud Platform, and Amazon Web Services has also reportedly been updated. Linux updates will also be issued shortly.
Fixes for Meltdown are easier to implement, while Spectre will be harder as true mitigations would require major changes to the way the chips work. It is unlikely, certainly in the short term, for Intel to attempt that. Instead, mitigations will focus on how programs interact with the CPUs. As US-CERT has warned, “[The] Underlying vulnerability is caused by CPU architecture design choices. Fully removing the vulnerability requires replacing vulnerable CPU hardware,” although that advice is no longer detailed in its updated vulnerability warning.
Applying patches will help to keep computers protected, but that may come at a cost. For example, the fix for the Meltdown vulnerability changes the way the computer works, which means the processor will have to work harder as it has to repeatedly access information from the memory – tasks that would otherwise not normally need to be performed.
That will undoubtedly have an impact on the performance of the machine. How much of a dip in performance can be expected? Some experts predict the changes could slow computers down by as much as 30%, which would certainly be noticed at times when processor activity is particularly high.