Tag Archives: Intel

Responding to the Meltdown and Spectre Vulnerabilities

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: 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: 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 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).

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.

Conclusion:
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.

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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.
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Thank you.

WPA2 KRACK Vulnerability: What you need to know

Last Sunday, the early signs of a vulnerability disclosure affecting the extensively used Wi-Fi protected access (WPA2) protocol were evident. The next day, disclosure of the vulnerability lead to more details. The vulnerability was discovered by  two researchers Mathy Vanhoef and Frank Piessens of the Katholieke Universiteit Leuven (KU Leuven) while examining OpenBSD’s implementation of the WPA2 four way handshake.

Why should this vulnerability be considered important?
On Monday 16th October, the KRACK (key re-installation attacks) vulnerability was disclosed. This vulnerability was found within the implementation of the WPA2 protocol rather than any single device making it’s impact much more widespread. For example, vulnerable devices include Windows, OpenBSD (if not already patched against it), Linux, Apple iOS, Apple macOS and Google Android.

If exploited this vulnerability could allow decryption, packet replay, TCP connection hijacking and if WPA-TKIP (defined) or GCMP (explained) are used; the attacker can inject packets (defined) into a victim’s data, forging web traffic.

How can an attacker exploit this vulnerability?
To exploit the vulnerability an attacker must be within range of a vulnerable Wi-Fi network in order to perform a man in the middle attack (MiTM)(defined). This means that this vulnerability cannot be exploited over the Internet.

This vulnerability occurs since the initial four way handshake is used to generate a strong and unique key to encrypt the traffic between wireless devices. A handshake is used to authenticate two entities (in this example a wireless router and a wireless device wishing to connect to it) and to establish the a new key used to communicate.

The attacker needs to manipulate the key exchange (described below) by replaying cryptographic handshake messages (which blocks the message reaching the client device) causing it to be re-sent during the third step of the four way handshake. This is allowed since wireless communication is not 100% reliable e.g. a data packet could be lost or dropped and the router will re-send the third part of the handshake. This is allowed to occur multiple times if necessary. Each time the handshake is re-sent the attacker can use it to gather how cryptographic nonces (defined here and here) are created (since replay counters and nonces are reset) and use this to undermine the entire encryption scheme.

How can I protect myself from this vulnerability?
AS described in this CERT knowledge base article.; updates from vendors will be released in the coming days and weeks. Apple (currently a beta update) and Microsoft already have updates available. OpenBSD also resolved this issue before the disclosure this week.

Microsoft within the information they published for the vulnerability discusses how when a Windows device enters a low power state the vulnerable functionality of the wireless connection is passed to the underlying Wi-Fi hardware. For this reason they recommend contacting the vendor of that Wi-Fi hardware to request updated drivers (defined).

Links to affected hardware vendors are available from this ICASI Multi-Vendor Vulnerability Disclosure statement. Intel’ security advisory with relevant driver updates is here. The wireless vendor, Edimax also posted a statement with further updates to follow. A detailed but easy to use list of many vendors responses is here. Since I use an Asus router, the best response I could locate is here.

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Update: 21st October 2017:
Cisco have published a security advisory relating to the KRACK vulnerability for its wireless products. At the time of writing no patches were available but the advisory does contain a workaround for some of the affected products.
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The above updates are software fixes but updates will also be made available for devices in the form of firmware updates e.g. for wireless routers, smartphones and Internet of Things (IoT)(defined) devices. For any wireless devices you own, please check with the manufacturer/vendor for available updates with the above CERT article and vendor response list detailing many of the common vendors.

Thank you.

Intel works with system vendors to address AMT vulnerability

In early May, Intel began the process of making available updates to resolve 2 critical security vulnerabilities within the hardware of corporate Intel systems. Security researchers located vulnerabilities within the co-processor which has the role of a management engine and to provide further features as part of Intel’s vPro technology. vPro allows IT teams to remotely administer systems (e.g. determine a systems status regardless of its condition, power on/power off, restart etc.) and provides capabilities including secure wiping of data should the device be lost or stolen.

Why should these vulnerabilities be considered important?
As documented within Intel’s advisory: The first vulnerability allows a remote attacker to gain system level privileges (the highest privileges available)(defined) thus allowing them to make any changes they wish to the affected system. This applies to systems with Intel Active Management Technology (AMT) or Intel® Standard Manageability (ISM) enabled.

The second vulnerability allows an attacker already located within your internal/corporate network to gain network or local system privileges on affected systems. This vulnerability affects AMT and systems with Intel Small Business Technology (SBT) enabled. Definitions for AMT, ISM and SBT are available from Intel. A useful FAQ on the vulnerabilities is available here.

Vulnerable systems are very likely to be in use by many corporate organisations and small businesses. The version numbers of the affected Intel technologies are listed within US-CERTs advisory. All Intel systems which have Intel Active Management Technology (AMT), Intel® Standard Manageability (ISM), and Intel® Small Business Technology enabled are vulnerable. Such systems have been in production for more than nine years.

It should be noted that only business configured devices have such enablement capabilities, the same vulnerabilities do not exist on consumer devices.  However, given the increasingly blurry distinction between user and business devices, especially with concepts such as Bring your own device (BYOD)(defined) these issues can easily be widespread and will take time to address. Intel has published steps which will help to identify affected systems.  A tool is also available from Intel’s download center.

For this vulnerability to be successfully exploited the Active Management Technology (AMT) must be configured to support remote administration.  This tool is not configured by default.

Moreover while the above mentioned three management technologies are vulnerable, the first vulnerability can only be exploited if Active Management Technology (AMT) is provisioned. If not provisioned, the second vulnerability applies.

These vulnerabilities are particularly severe since the management engine co-processor (mentioned above) can access any memory region within an affected system without the primary Intel processor (CPU)(defined) being aware of it. The co-processor can send, receive, read/write data travelling on your network below the level at which firewalls operate thus bypassing them. The management engine can also read and write to the systems storage device (a hard drive) upon the successful authorisation of a user. The co-processor also has read and write access to the devices screen (your monitor) all while remaining undetected and unlogged (events are not captured within the logs of your operating systems making detection by SIEMs (defined) unviable).

How can I protect myself from these vulnerabilities?
Intel has created a list of affected vendors which links to their respective websites including the status of the availability of updates as well as already completed/available updates.

While the preparation of updates is in progress, the following mitigation options are available:

  1. Un-provisioning Intel manageability SKU (stock keeping unit) clients to mitigate unprivileged network attacker from gaining system privileges (Unprovisioning Tool v1.0)
  2. Disabling or removing the Local Manageability Service (LMS) to mitigate unprivileged local attacker from gaining system privileges
  3. Optionally configuring local manageability configuration restrictions

Unfortunately it will take time for vendors to issue updates for all affected systems. If you are in any doubt if your systems are affected, please contact them. In addition, please continue to access the list of vendor websites (provided above) to monitor when the updates to your systems become available. If due dates are instead present at this time, you can schedule a downtime window for these systems to be updated.

Thank you.

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Aside:
What is a stock keeping unit (SKU)?

It refers to a specific item stored to a specific location. The SKU is intended as the most disaggregated level when dealing with inventory (Source)
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