Tag Archives: Linux

Responding to the Intel Spoiler Vulnerability

Updated: 20th March 2019
The Intel Spoiler vulnerability is not as bad as predicted. Software developers should continue to use safer code development practices.

After the disclosure earlier this month of this vulnerability Intel have provided further information on how it affects their microprocessors. They have clarified that the Spoiler exploit by itself does not reveal secret data and is not a speculative execution side channel method:

Other good news is that existing mitigations such as KPTI (kernel page table isolation) reduce the risk of leaking data across privilege levels. They again confirmed that side channel safe software development practices such as “ensuring execution time and control flows are identical regardless of secret data” will mitigate classic side channel methods enabled by the Spoiler exploit. Furthermore, they confirmed memory modules which are already mitigated against Rowhammer attacks remain protected against the Spoiler exploit.

Lastly AMD provided formal confirmation that their microprocessors are not vulnerable after preliminary findings suggested they weren’t vulnerable. AMD’s statement is available from this link.

Thank you.

Original Post:
Earlier this month a new vulnerability was disclosed in a research paper titled “Spoiler: Speculative load hazards boost Rowhammer and cache attacks”.

TL DR: Mitigating this newly disclosed vulnerability is the job of software developers to work around using safer code development practices. Mitigating this issue in hardware will take longer since current measures cause too much of a performance penalty.

Why should this vulnerability be considered important?
Using this new method; attackers are likely to find existing cache and memory Rowhammer attacks easier to carry out. In addition, JavaScript (defined) attacks which can take long periods of time may be shortened to mere seconds. The paper contains a cache prime and probe technique to leak sensitive data using JavaScript.

This Spoiler vulnerability can be used by attackers (who MUST have already compromised your system) to extract sensitive information from the systems memory (RAM). An attack does not require elevated privileges.

What CPUs (microprocessors / computer chips) are affected?
This vulnerability affects Intel processors only; first generation Intel Core (from early 2006) and later are affected. ARM and AMD processors are not affected. Any system with an Intel Core processor is affected regardless of the operating they are using namely Linux, Unix, Apple macOS and Windows can be all affected.

How does this vulnerability achieve the above results?
The security researchers who authored the paper found a vulnerability in the memory order buffer that can be used to gradually reveal information about the mappings of physical memory to non-privileged software processes (in other words; applications). This technique also affects virtual machine (VM) and sandboxed (defined) environments.

The technique works by understanding the relationship between virtual and physical memory by timing the speculative load and store operations to these areas while looking out for discrepancies which disclose the memory layout to you. With this information an attacker knows where to focus their efforts.

Intel’s proprietary implementation of the memory subsystem (memory disambiguation) is the root cause of the vulnerability. When a physical address conflict (the address/area is already in use) occurs, the algorithm leaks the access timings. The algorithm in the researcher’s words works as follows “Our algorithm, fills up the store buffer within the processors with addresses that have the same offset but they are in different virtual pages. Then, we issue a memory load that has the same offset similarly but from a different memory page and measure the time of the load. By iterating over a good number of virtual pages, the timing reveals information about the dependency resolution failures in multiple stages.”

How can this vulnerability be mitigated/patched?
This vulnerability lies within the memory disambiguation algorithm which won’t be trivial to resolve anytime soon. Since this vulnerability is not related to last years Spectre vulnerability; mitigations for that vulnerability don’t help here. Current Spoiler mitigations have too much of performance penalty. At this time, Intel has issued the following statement:

“Intel received notice of this research, and we expect that software can be protected against such issues by employing side channel safe development practices. This includes avoiding control flows that are dependent on the data of interest. We likewise expect that DRAM modules mitigated against Rowhammer style attacks remain protected. Protecting our customers and their data continues to be a critical priority for us and we appreciate the efforts of the security community for their ongoing research.”

The side channel safe development practices are linked to below:

Software Guidance for Security Advisories

Addressing Hardware Vulnerabilities

Thank you.

February 2019 Update Summary

Earlier today Microsoft made available 13 bulletins and 3 advisories resolving 74 vulnerabilities (more formally known as CVEs (defined)) respectively. As always more details are available from Microsoft’s monthly summary page.

Also today Adobe released scheduled updates for the products listed below addressing 75 CVEs in total:

Adobe Acrobat and Reader: 71x priority 2 CVEs resolved (43 of the 75 are Critical, the remainder are Important severity)

Adobe ColdFusion: 2x priority 2 CVEs resolved

Adobe Creative Cloud Desktop Application: 1x priority 3 CVE resolved

Adobe Flash Player: 1x priority 2 CVE resolved

If you use the affected Adobe products; due to the public disclosure (defined) of CVE-2019-7089 as a zero day (defined) vulnerability, please install the Adobe Acrobat and Reader updates first followed by Flash Player and the remaining updates. I provide more detail on the zero day vulnerability in a separate post.

As we are accustomed to Microsoft’s updates come with a long list of Known Issues that will be resolved in future updates or for which workarounds are provided. They are listed below for your reference:


You can monitor the availability of security updates for most your software from the following websites (among others) or use one of the utilities presented on this page:

US Computer Emergency Readiness Team (CERT) (please see the “Information on Security Updates” heading of the “Protecting Your PC” page):


A further useful source of update related information is the Calendar of Updates.

News/announcements of updates in the categories of General SoftwareSecurity Software and Utilities are available on their website. The news/announcements are very timely and (almost always) contain useful direct download links as well as the changes/improvements made by those updates (where possible).

If you like and use it, please also consider supporting that entirely volunteer run website by donating.

For this month’s Microsoft updates, I will prioritize the order of installation below:
Microsoft Edge and Internet Explorer (multiple versions of Edge and IE affected)

Microsoft GDI+

Scripting Engine (CVE-2019-0590 , CVE-2019-0591 , CVE-2019-0593 , CVE-2019-0640  ,
, CVE-2019-0648 , CVE-2019-0649  , CVE-2019-0651 , CVE-2019-0652 , CVE-2019-0655 , CVE-2019-0658)

Windows DHCP

Microsoft Exchange

Microsoft SharePoint and CVE-2019-0604

Please install the remaining updates at your earliest convenience.

As usual; I would recommend backing up the data on any device for which you are installing updates to prevent data loss in the rare event that any update causes unexpected issues. I have provided further details of updates available for other commonly used applications below.

Thank you.

Nvidia Graphics Drivers:
8 security vulnerabilities with the most severe having a CVSS V3 (defined) base score of 8.8 have been resolved within Nvidia’s graphics card drivers (defined) in February. These vulnerabilities affect Linux FreeBSD, Solaris and Windows. The steps to install the drivers are detailed here (and here) for Ubuntu and here for Linux Mint. Windows install steps are located here. If you use affected Nvidia graphics card, please consider updating your drivers to the most recent available.

In the 3rd week of February; 7-Zip version 19.00 was released. While it is not designated as a security update; the changes it contains appear to be security related. While 7-Zip is extremely popular as a standalone application; other software such as Malwarebytes Anti-Malware, VMware Workstation and Directory Opus (among many others) all make use of 7-Zip. Directory Opus version 12.2.2 Beta includes version 19.00 of the 7-Zip DLL.

If you use these software applications or 7-Zip by itself, please update these installed applications to benefit from these improvements.

– Encryption strength for 7z archives was increased:
the size of random initialization vector was increased from 64-bit to 128-bit, and the pseudo-random number generator was improved.
– Some bugs were fixed.

If you are using the standalone version and it’s older than version 19, please consider updating it.

Mozilla Firefox
In mid-February Mozilla issued updates for Firefox 65 and Firefox ESR (Extended Support Release) 60.5:

Firefox 65.0.1: Resolves 3x high CVEs (defined)

Firefox 60.5.1: Resolves 3x high CVEs

As always; details of how to install updates for Firefox are here. If Firefox is your web browser of choice, if you have not already done so, please update it as soon as possible to benefit from changes such as improvements to Netflix playback, color management on Apple macOS and resolving audio/video delays during WebRTC calls etc.

Wireshark 3.0.0, 2.6.7 and 2.4.13
v3.0.0: 0 security advisories (new features and benefits discussed here and here)

v2.6.7: 3 security advisories

v2.4.13: 3 security advisories

As per standard process Linux distributions can obtain this update using the operating systems standard package manager (if the latest version is not installed automatically using the package manager you can instead compile the source code (v3.0.0, v2.6.6 or v2.4.12). This forum thread and this forum thread may also be helpful to you with installing Wireshark on your Linux based system.

For Mac OS X and Windows, the update is available within the downloads section of the Wireshark website. In addition, a detailed FAQ for Wireshark is available here.

Note: from this post onwards, I will only report on the most recent (v3.0) and previous branches (v2.6) of Wireshark.

Thank you.

Linux and Windows Address Page Cache Vulnerabilities

In early January security researchers located further vulnerabilities in how Windows and Linux operating systems use a memory page cache.

How severe are these vulnerabilities and what is their impact?
One of the co-authors of the academic paper disclosing these vulnerabilities described the work as mostly “a matter of academic interest” meaning that attackers are less likely to take advantage of these vulnerabilities.

Local attacks:
For the localised rather than remote variant of utilizing these vulnerabilities; the attacker must already have gained access to the victim system to read the target memory page. The attacker could do this by “[having a] malicious process on the operating system or when processes run in sandboxes that have shared files”.

Other actions an attacker could potentially carry out are:

• Cloning an open window and replacing the legitimate application window
• Gathering the root (Linux) or administrator (Windows) password

Remote attack:
To exploit the vulnerabilities remotely; the researchers leveraged “timing differences between memory and disk access, measured on a remote system, as a proxy for the required local information”. This was achieved by measuring the times when soft page faults (the page is erroneously mapped, with the help of a process that runs on a remote server) occurred. The researchers were successful in sending data covertly from an unprivileged malicious process within the victim system to a remote server fulfilling the role of a web server. They used a technique from previous research namely the NetSpectre attack to distinguish cache hits and misses over a network connection. This was successful on systems with mechanical hard drives (HDDs) and solid-state disks (SSDs). SSDs were more complex since the timing differences were smaller but the researchers compensated by using larger files to distinguish between cache hits and misses.

How can I protect my organization/myself from these vulnerabilities?
Since these vulnerabilities are more academic in nature; attackers are less likely to exploit them. Linus Torvalds has explained that the code to resolve this vulnerability has been checked in and is undergoing testing before being more widely rolled out. For Windows; Build 18305 of the upcoming Windows 19H1 (otherwise known as Version 1903) due for release in April 2019 contains fixes for these vulnerabilities. It is anticipated Microsoft will back-port this patch to earlier Windows versions.

In addition; the mitigations for the Spectre vulnerabilities from last year should address the remote attack vector using the NetSpectre attack method.

Why are there so many timing attacks being disclosed lately?
Since modern systems rely on timing for almost every component e.g. the CPU (internal caches and registers respond in nanoseconds (ns)), the memory/RAM (e.g. CAS latency), HDDs (measured in milliseconds (ms) e.g. 8.9 ms), SSDs (e.g. 0.05 ms , much faster) we are likely to continue to see further vulnerabilities disclosed as further scrutiny is applied to devices and architectures that have been in use for many years.

E.g. the affected code from Linux was timestamped in 2000 and stated that further revision should be carried out when more information was known. 19 years later we know more and are revising that code. It’s a similar situation with Windows where the revised code works to ensure low privilege processes can no longer access page cache information or shared cache information. As The Register points out; “something complex that’s just working can remain untouched for a very long time, lest someone breaks it” and is more likely to contain vulnerabilities since nobody has taken the time to look for what has been there for years.

Thank you.

Oracle VirtualBox Zero Day Disclosed

In early November a security researcher publicly disclosed (defined) a zero day (defined) vulnerability within Oracle’s VirtualBox virtualisation software.

How severe is this vulnerability?
In summary; this vulnerability is serious but it could have been worse. In order to exploit it, an attacker would first need to have obtained elevated privileges on your system; root (defined) in the case of Linux and administrator (defined) in the case of Windows. Using this privilege the attacker can leverage the exploit to escape from the confines of the virtual machine (VM)(defined) into the system which hosts the virtual machine (in other words; the system which houses the virtual machine within its physical infrastructure). Once outside of the virtual machine the attacker must then elevate their privileges again since breaking out of the VM only gives them user level/standard privileges and not elevated privileges in the physical system. Thus the attacker would then need to use a separate exploit for another vulnerability (not related to this VirtualBox flaw) to elevate their privileges again to become root/admin within the physical system.

Obviously; the consequences of exploiting this vulnerability on a shared service/cloud infrastructure system would be more serious since multiple users would be affected all at once and the further exploitation of the resulting host systems could potentially provide the attacker with control over all the virtual machines.

How can an attacker exploit this vulnerability?
VirtualBox makes use of the Intel Pro/1000 MT Desktop (82540EM) network adapter to provide an internet connection to the virtual machines it manages. The attacker must first turn off this adapter in the guest (virtualised) operating system. Once complete they can then load a custom Linux kernel module (LKM)(defined) (this does not require a reboot of the system). That custom LKM contains the exploit derived from the technical write up provided. That new LKM loads its own custom version of the Intel network adapter. Next the LKM exploits a buffer overflow (defined) vulnerability within the virtualised adapter to escape the guest operating system. The attack must then unload the custom LKM to re-enable the real Intel adapter to resume their access to the internet.

How can I protect myself from this vulnerability?
While this is a complex vulnerability to exploit (an attacker would need to chain exploits together in order to elevate their privilege on the host system after escaping the VM), the source code needed to do so is available in full from the researcher’s disclosure; increasing the risk of it being used by attackers.

At the time of writing; this vulnerability has not yet been patched by VirtualBox. It affects versions 5.2.20 and earlier when installed on Ubuntu version 16.04 and 18.04 x86-64 guests (Windows is believed to be affected too). While a patch is pending; you can change the network card type to PCnet or Para virtualised Network. If this isn’t an option available or convenient for you; you can an alternative to the NAT mode of operation for the network card.

Thank you.

Vendors Respond to Foreshadow (L1TF) Vulnerabilities

Yesterday, academic and security researchers publically disclosed (defined) 3 new vulnerabilities affecting Intel CPUs (AMD and ARM are not affected).

What are these new vulnerabilities and what can they allow an attacker to do?
The first vulnerability known as Foreshadow or CVE-2018-3615 is used to extract data from an Intel SGX (Software Guard Extensions)(defined) secure enclave (area) by creating a shadow copy of the SGX protected data but that copy does not have the protection of SGX and can be read/accessed by the attacker. The attacker can also re-direct speculative execution into copying further private/sensitive into the shadow copied area while at the same time making it appear that area is genuine and thus has the same protection as the real SGX protected data.

The second vulnerability (part of a wider Foreshadow Next Generation (NG) group of two variants) known as CVE-2018-3620 allows the reading of data copied into the level 1 cache (defined) of a CPU (defined) when that data is in use by a computer operating system e.g. Red Hat Linux, Apple macOS or Microsoft Windows.

The third vulnerability is the second and final variant of the Foreshadow NG group known as CVE-2018-3646.  This affects virtualised environments. If a CPU thread (defined) being directed by an attacker is able to read the level 1 cache of a CPU that is also shared by another thread by a victim user (within another virtualised environment but using the same physical CPU) while that request will be blocked; if the information the attacker is looking to steal is in the level 1 cache they may still get a glimpse of this information.

How can I protect myself from these new vulnerabilities?
For the first and second vulnerabilities; the microcode (defined)/firmware (defined) updates made available earlier this year coupled with the newly released updates for operating systems linked to below will mitigate these two issues.


For the third vulnerability; affecting virtualised (defined) environments there are operating system updates and microcode/firmware updates available that will occasionally clear the contents of the level 1 cache meaning that when the attacker attempts to read it they will not receive any benefit from doing so. Partially removing the usefulness of the cache will have a performance impact from a few percent up to 15 percent in the worst case scenario.

However to completely mitigate this third vulnerability a capability known as Core Scheduling needs to be leveraged. This ensures that only trusted/non attacker controlled virtual machines have access to the same thread (this capability is already available in some virtual machine (hypervisor)(defined) environments).

However in some environments if it cannot be guaranteed that all virtual machines are trustworthy the disabling of Intel Hyper Threading (this means that only 1 thread will work per CPU core)(otherwise known as simultaneous multi-threading (SMT)(defined)) may be necessary and will more significantly impact performance than just the level 1 cache clearing.

In summary for this third vulnerability; depending upon the virtualised environment you are using and the trustworthiness of the virtual machines you are using will determine how many of the these extra security measure you will need to take.

To be clear I am NOT advocating that Intel Hyper Threading/SMT be disabled EN MASSE for security reasons. As per the advice in the linked to advisories (below)(specifically Intel and VMware) ; you MAY wish to disable Intel Hyper Threading/SMT to mitigate the third vulnerability (CVE-2018-3646) depending upon the environment your virtualised machines are operating.

This Ars Technica article explains it very well: “if two virtual machines share a physical core, then the virtual machine using one logical core can potentially spy on the virtual machine using the other logical core. One option here is to disable hyperthreading on virtual-machine hosts. The other alternative is to ensure that virtual machines are bound to physical cores such that they don’t share.”


Please find below links to vendor responses on these vulnerabilities as well as videos that can help in understanding these vulnerabilities:

Thank you.


Foreshadow Vulnerability Official Website:

Intel’s Blog Post:

Intel’s FAQ Page:

Intel’s Security Advisory:

Intel’s Software Developer Guidance:

Red Hat’s Security Advisory:

Linux Kernel Patch:

Oracle’s Security Advisory:

Amazon Web Services’ Security Advisory:

Google Cloud Security’s Blog Post:

Microsoft Windows Azure’s Guidance:

Microsoft’s Windows Security Advisory (high level details):

Microsoft’s Technical Analysis of the Foreshadow Vulnerabilities:

VMware Security Advisories:


Foreshadow Video (explains the first vulnerability very well):

Intel’s Video (explains all 3 vulnerabilities):

Demonstration of the Foreshadow attack:

Red Hat’s Video (explains all 3 vulnerabilities):

Red Hat’s In-depth video of the 3 vulnerabilities:


Intel Lazy Floating Point Vulnerability: What you need to know

Update: 24th July 2018:
I have updated the list of vendor responses below to include further Red Hat versions and CentOS:

Red Hat Enterprise Linux 6:

Red Hat Enterprise Linux 5 and 7:

CentOS 6:

CentOS 7:


On Wednesday of last week, a further vulnerability affecting Intel CPUs (defined) was disclosed.

TL;DR: Keep your operating system up to date and you should be fine.

What makes this vulnerability noteworthy?
According to Intel’s security advisory; this is an information disclosure issue. Similar to Spectre/Meltdown the flaw is the result of a performance optimization (used when saving and restoring the current state of applications as a system switches from one application to another). A feature known as Lazy Floating Point (defined) Unit (FPU) is used to save and restore registers (defined) within the CPU used to store floating point numbers (non-integers numbers, namely decimal numbers).

The issue is that these registers may be accessed by another application on the same system. If the registers are storing for example results of performing cryptographic equations for a key you have just created or used to decrypt data, the attacker could use this data to infer what the actual key is. The same applies for any type of data the registers store; that data can be used to infer what the previous contents were via a speculative execution side channel.

This vulnerability has been rated as moderate since it is difficult to exploit via a web browser (in contrast to Spectre) and the updates will be a software update only; no microcode (defined) and/or firmware (defined) updates will be necessary. With exploitation via a web browser being difficult; this vulnerability will likely instead be exploited from the victim system (at attacker will need to have already compromised your system).

How can I protect myself from this vulnerability?
Please note; AMD CPUs are NOT affected by this vulnerability.

The following vendors have responded to this vulnerability with software updates now in progress. Separately Red Hat has completed their updates for Red Hat Linux 5, 6 and 7 (with further applicable updates still in progress).

Other vendors responses are listed below. Thank you:

Amazon Web Services

Apple (currently release notes for an update to macOS to resolve the vulnerability)


Intel’s Security Advisory


Microsoft Windows


Xen Project

Responding to the Meltdown and Spectre Vulnerabilities

Please scroll down for more updates to this original post.
Update: 23rd May 2018:
For information on the Spectre NG vulnerabilities please refer to this new blog post

Thank you.

Original Post:
Earlier in January updates for Linux, Apple and Windows were made available to work towards addressing the 3 security vulnerabilities collectively known as Meltdown and Spectre.

Why should these vulnerabilities be considered important?
I’ll provide a brief summary of the two categories of vulnerabilities:

Meltdown (CVE-2017-5754): This is the name of the vulnerability discovered that when exploited by an attacker could allow an application running with standard privileges (not root or elevated privileges) to read memory only intended for access by the kernel.

Spectre (Variant 1: CVE-2017-5753 ; Variant 2: CVE-2017-5715): This is a category of two known vulnerabilities that erode the security boundaries that are present between applications running on a system. Exploitation can allow the gathering of information from applications which could include privileged information e.g. usernames, password and encryption keys etc. This issue can be exploited using a web browser (e.g. Apple Safari, Mozilla Firefox, Google Chrome, Microsoft Edge (or IE) by using it to record the current time at very short intervals. This would be used by an attacker to learn which memory addresses were cached (and which weren’t) allowing the attacker to read data from websites (violating the same-origin policy) or obtain data from the browser.

Browser vendors have responded by reducing the precision of JavaScript timing and making it more unpredictable while other aspects of JavaScript timing (using the SharedArrayBuffer feature) have been disabled.

More in-depth (while still being less technical) descriptions of these issues are available here , here and here.

How can I protect myself from these vulnerabilities?
Since these vulnerabilities are due to the fundamental architecture/design of modern CPUs; it is not possible to fully address them. Instead a combination of software fixes and microcode updates (defined) is more a viable alternative than re-designing the established architecture of modern CPUs.

In-depth lists of updates available from multiple vendors are available here and here. I would suggest glancing at the affected vendors and if you own a device/product from them; checking if you are affected by these vulnerabilities. A list of BIOS (defined) updates from multiple vendors are available here. Google Chrome has a Site Isolation mode that can mitigate these vulnerabilities which will be more comprehensively addressed in Chrome version 64 scheduled for release last this month.

At this time my systems required updates from Google, Mozilla, Microsoft, Apple, VMware, Asus, Lenovo and Nvidia. Many of many existing desktops are unlikely to receive microcode and BIOS updates due to be more than 3 years old. However my Windows 10 laptop has received a BIOS update from the manufacturer.

Are there disadvantages to installing these updates?
While these updates increase security against these vulnerabilities; performance issues and stability issues (Intel and AMD) after the installation of these updates have been reported. These vary in severity but according to Intel and Microsoft the updates will be refined/optimised over time.

Benchmarks (for desktops) made available by TechSpot show negligible impact on most tasks that would stress a CPU (defined). However any work that you perform which makes of large files e.g. databases may be significantly impacted by the performance impact these updates have when accessing files on disk (mechanical and solid state). For laptops the slowdown was felt across almost all workload types. Newer and older silicon were inconsistently impacted. At times even some Intel 8th generation CPUs were impacted more than 5th generation CPUs.

Details of the anticipated performance impact for Linux, Apple macOS (and iOS) and Windows are linked to. Further reports of reduced performance from Intel and Apple devices have also been recorded. Further details of a feature known as PCID (Process-Context Identifiers) within more recent CPUs which will help reduce the performance impact are provided here. For Intel CPUs, 4th generation Core CPUs and later should include it but any CPU manufactured after 2011 should have it (one of my CPUs; a Core i7 2600K has this feature, verified using Sysinternals Coreinfo). A full list of Intel CPUs affected by these vulnerabilities is here.

With the widely reported stability and performance issues present it is your decision if you install the necessary updates now or wait until further refinements. If you experience issues, please report them to the manufacturers where possible and within online forums if not. More refined updates will only be created if a need to do so is established.

I’m in the process of updating my systems but will benchmark them before and after each updates to determine an impact and make a longer term decision to keep the updates or uninstall them until further versions become available. I’ll update this post as I gather more results.

Update: 16th January 2018:
A newly released free utility from Gibson Research (the same website/author as the well-known ShieldsUp firewall tester) named InSpectre can check if your Windows system has been patched against Meltdown and Spectre and can give an indication of how much the performance of your system will be affected by installing and enabling the Windows and/or the BIOS updates.

Please note: I haven’t tried this utility yet but will this weekend (it will help with the tests I’m carrying out (mentioned above). I’ll update this post when I have tried out this utility.

Thanks again.

Update: 24th January 2018:
As promised I gathered some early results from a selection of CPUs and the results for all but recent CPUs are evidence they will experience a potentially noticeable performance drop:

CPUs supporting PCID (obtained using Sysinternals Coreinfo):
Intel Core i7 Extreme 980X @ 3.33 GHz
Intel Core i7 2600K @ 3.8 GHz
Intel Core i5 4590T @ 3.3 GHz
Intel Core i7 6500U (laptop CPU) @ 2.5 GHZ

CPUs supporting INVPCID (obtained using Sysinternals Coreinfo):
Intel Core i5 4590T @ 3.3 GHz
Intel Core i7 6500U (laptop CPU) @ 2.5 GHZ

Explanations of the purpose and relevance of the PCID and INVPCID CPU instructions are available from this Ars Technica article. The results from InSpectre only show positive results when both PCID and INVPCID are present backing up the observations within the above linked to Ars Technica article (that the updates take advantage of the performance advantages of these instructions when both are present).

The results from InSpectre back up these findings by stating that the 980X and 2600K will not deliver high performance protection from Meltdown or Spectre. Since my PCs are mainly used for more CPU intensive tasks (rather than disk intensive) e.g. games and Folding@Home; I still don’t expect too much of a performance decrease. The older CPUs are due for replacement.

You may ask; “why am I so concerned with the performance impact of these updates?” The answer is that significant time and investment has been made into the above systems for them to perform at peak performance for the intended tasks I use them for. Performance and security are both very important to me and I believe there should only be a small trade off in performance for better security.

My next step will be to benchmark the CPU, hard disk and GPU of each system before and after installing each update. I will initially do this for the 6500U and 2600K systems and provide these results. The categories of updates are listed below. I will keep you informed of my findings.

Thank you.
Update 1: Software updates from Microsoft for Meltdown and Spectre
Update 2: Firmware update (where available)
Update 3: Nvidia / AMD GPU driver update

Update: 13th February 2018:
Sorry for the long delay (I was travelling again for my work). The above benchmarking is now taking place and I will make the results available as soon as possible. Thanks for your understanding.

Update: 27th February 2018
Earlier last week Intel made available further microcode updates for more CPUs. These updates seek to address variant 2 of the Spectre vulnerability (CVE-2017-5715). Updates are now available for the CPUs listed below.

As before, please refer to the manufacturer of your motherboard of your system for servers, desktops and laptops or the motherboard manufacturer for any custom built systems you may have to determine if these updates have been made available for your specific systems. Further information for corporate system administrators containing details of the patching process is available within this link (PDF):

  • Kaby Lake (Intel 7th Generation Core CPUs)
  • Coffee Lake (Intel 8th Generation Core CPUs)
  • Further Skylake CPUs (Intel 6th Generation Core CPUs)
  • Intel Core X series (Intel Core i9 CPUs e.g. in the 7900 and 7800 model range)
  • Intel Xeon Scalable (primarily targeted at data centres)
  • Intel Xeon D (primarily targeted at data centres)

Information on patches now available for OpenBSD and FreeBSD are located within the following links:

OpenBSD mailing list
The Register: OpenBSD Patch now Available

FreeBSD Wiki
Softpedia: Spectre and Meltdown mitigations now available

Update: 1st April 2018
As vendors have responded to these vulnerabilities; updates have been released for many products. I will describe these updates in more detail below. Apologies if I have omitted any, this isn’t intentional but the list below should still be useful to you:

Google ChromeOS:
Following the release of ChromeOS 64 in February which provided updates against the Meltdown and Spectre vulnerabilities, ChromeOS 65 includes further mitigations against these vulnerabilities including the more efficient Retpoline mitigation for Spectre variant 2.

Sony Xperia:
In late February Sony made available updates which include mitigations for Meltdown and Spectre for their Xperia X and Xperia X Compact phones which brings the build number to 34.4.A.2.19

Microsoft Issues Microcode Updates:
As previously mentioned when this blog post was first published; updates for the Meltdown and Spectre vulnerabilities are made up of software updates, microcode updates and firmware (BIOS updates) and GPU drivers.

Due to the complexity of updating the firmware of computer systems which is very specific and potentially error prone (if you apply the wrong update to your device it can render it useless, meaning it will need to be repaired/replaced (which is not always possible) Microsoft in early March began to issue microcode driver updates (as VMware describes they can be used as substitutes for firmware updates). Microcode updates have been issued in the past to address CPU reliability issues when used with Windows.

Intel Firmware Updates:
As with previous microcode updates issued by Intel in late February; these updates seek to resolve variant 2 of the Spectre vulnerability (CVE-2017-5715).

While Intel has issued these updates; they will be made available separately by the manufacturer of your motherboard of your system for servers, desktops and laptops or the motherboard manufacturer for any custom built systems you may have. You will have to determine from the updates those vendors issue if they are available for the products that you own.

Unfortunately not all systems will receive these updates e.g. most recent system was assembled in 2014 and has not received any updates from the vendor; the vendor has issued updates on their more recent motherboards. Only my 2016 laptop was updated. This means that for me; replacing the systems gradually is the only means of addressing variant 2 of the Spectre vulnerability.

Intel’s updates are for the Broadwell (5th generation CPUs i.e. 5000 series) and Haswell (4th generation CPUs i.e. 4000 series).

Microsoft Surface Pro:
Earlier this week Microsoft released firmware updates for their Surface Pro which mitigate the Meltdown and Spectre vulnerabilities. This link provides further details and how to install the updates.

Microsoft Issues Further Security Update on the 29th March:
As noted in my separate post; please refer to that post for details of a security update for Windows 7 SP1 64 bit and Windows Server 2008 R2 SP1 64 bit that resolve a regression (an un-intentional coding error resulting in a previously working software feature no longer working, alternative definition here) which introduced an additional elevation of privilege (defined) security vulnerability in the kernel (defined) of those Windows versions.

Microsoft Offers Bug Bounty for Meltdown and Spectre vulnerabilities:
Microsoft have announced bug bounties from $5000 to $250,000 to security researchers who can locate and provide details of exploits for these vulnerabilities upon Windows, Azure and Microsoft Edge.

If such a programme is successful it could prevent another instance of needing to patch further related vulnerabilities after the issues have been publicly disclosed (defined). This is sure to assist the system administrators of large organisations who currently in the process of deploying the existing updates or who may be testing systems on a phased basis to ensure performance is not compromised too much.

Further details are available from this link.

Update: 6th April 2018
Earlier this week, Intel issued a further progress update for the deployment of further microcode for their CPUs.

A further 5 families of CPUs have now completed testing and microcode updates are available. These families are:

    • Arrandale
    • Clarkdale
    • Lynnfield
    • Nehalem
    • Westmere

However a further 9 families will not receive such updates for the reasons listed below. Those families are:

      • Micro-architectural characteristics that preclude a practical implementation of features mitigating [Spectre] Variant 2 (CVE-2017-5715)
      • Limited Commercially Available System Software support
      • Based on customer inputs, most of these products are implemented as “closed systems” and therefore are expected to have a lower likelihood of exposure to these vulnerabilities.


      • Bloomfield
      • Clarksfield
      • Gulftown
      • Harpertown Xeon
      • Jasper Forest
      • Penryn
      • SoFIA 3GR
      • Wolfdale
      • Yorkfield

This announcement from Intel means my Intel Core i7 Extreme 980X (from 2010) won’t receive an update. This system isn’t used very much on the internet and so the impact is limited. I am hoping to replace this system in the near future too.


Please review the updated PDF made available by Intel (I can upload the PDF to this blog if Intel place it behind an account which requires sign in. At this time the PDF link still works).

As before; please monitor the websites for the manufacturer of your system for servers, desktops and laptops or the motherboard manufacturer for any custom built systems you may have to determine if these updates have been made available for your specific systems.

Thank you.

BranchScope Vulnerability Disclosed:
In a related story; four security researchers from different universities responsibly disclosed (defined) a new side channel attack affecting Intel CPUs. This attack has the potential to obtain sensitive information from vulnerable systems (a similar result from the existing Meltdown and Spectre vulnerabilities).

Further details of this attack named “BranchScope” are available in this Softpedia article and this paper from the researchers. Within the above article Intel responded to this attack stating that this vulnerability is similar to known side channel and existing software mitigations (defined) are effective against this vulnerability. Their precise wording is provided below.

Thank you.

An Intel spokesperson has provided the following statement:

“We have been working with these researchers and have determined the method they describe is similar to previously known side channel exploits. We anticipate that existing software mitigations for previously known side channel exploits, such as the use of side channel resistant cryptography, will be similarly effective against the method described in this paper. We believe close partnership with the research community is one of the best ways to protect customers and their data, and we are appreciative of the work from these researchers.”

Update: 13th April 2018
AMD have issued microcode (defined) updates for Windows 10 Version 1709 to enhance the protection of their customer’s against variant 2 (CVE-2017-5715) of the Spectre vulnerability. Further details of these updates are available within these KB articles: KB4093112 and KB3073119

Thank you.

Update: 18th May 2018
Please refer to the beginning of the May and April security update summaries for further updates related to addressing Spectre variant 2 (v2).