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A reasonably secure operating system for personal computers.

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QSB #40: Information leaks due to processor speculative store bypass (XSA-263)
https://www.qubes-os.org/news/2018/05/24/qsb-40/

Dear Qubes Community,

We have just published Qubes Security Bulletin (QSB) #40: Information
leaks due to processor speculative store bypass (XSA-263). The text of
this QSB is reproduced below. This QSB and its accompanying signatures
will always be available in the Qubes Security Pack (qubes-secpack).

View QSB #40 in the qubes-secpack:

https://github.com/QubesOS/qubes-secpack/blob/master/QSBs/qsb-040-2018.txt

Learn about the qubes-secpack, including how to obtain, verify, and
read it:

https://www.qubes-os.org/security/pack/

View all past QSBs:

https://www.qubes-os.org/security/bulletins/

View XSA-263 in the XSA Tracker:

https://www.qubes-os.org/security/xsa/#263



---===[ Qubes Security Bulletin #40 ]===---

2018-05-24


Information leaks due to processor speculative store bypass (XSA-263)

Summary
========

On 2018-05-21, the Xen Security Team published Xen Security Advisory
263 (CVE-2018-3639 / XSA-263) [1] with the following denoscription:

| Contemporary high performance processors may use a technique commonly
| known as Memory Disambiguation, whereby speculative execution may
| proceed past unresolved stores. This opens a speculative sidechannel
| in which loads from an address which have had a recent store can
| observe and operate on the older, stale, value.

Please note that this issue was neither predisclosed nor embargoed.
Consequently, the Qubes Security Team has not had time to analyze it in
advance of issuing this bulletin.

Impact
=======

According to XSA-263, the impact of this issue is as follows:

| An attacker who can locate or create a suitable code gadget in a
| different privilege context may be able to infer the content of
| arbitrary memory accessible to that other privilege context.
|
| At the time of writing, there are no known vulnerable gadgets in the
| compiled hypervisor code. Xen has no interfaces which allow JIT code
| to be provided. Therefore we believe that the hypervisor itself is
| not vulnerable. Additionally, we do not think there is a viable
| information leak by one Xen guest against another non-cooperating
| guest.
|
| However, in most configurations, within-guest information leak is
| possible. Mitigation for this generally depends on guest changes
| (for which you must consult your OS vendor) *and* on hypervisor
| support, provided in this advisory.

In light of this, XSA-263 appears to be less severe than the related
Spectre and Meltdown vulnerabilities we discussed in QSB #37 [2].

Patching
=========

The specific packages that resolve the problems discussed in this
bulletin are as follows:

For Qubes 3.2:
- Xen packages, version 4.6.6-41

For Qubes 4.0:
- Xen packages, version 4.8.3-8

The packages are to be installed in dom0 via the Qubes VM Manager or via
the qubes-dom0-update command as follows:

For updates from the stable repository (not immediately available):
$ sudo qubes-dom0-update

For updates from the security-testing repository:
$ sudo qubes-dom0-update --enablerepo=qubes-dom0-security-testing

A system restart will be required afterwards.

These packages will migrate from the security-testing repository to the
current (stable) repository over the next two weeks after being tested
by the community.

If you use Anti Evil Maid, you will need to reseal your secret
passphrase to new PCR values, as PCR18+19 will change due to the new
Xen binaries.

In addition, Intel Corporation has announced that microcode updates
will be available soon [3]:

| Variant 3a is mitigated in the same processor microcode updates as
| Variant 4, and Intel has released these updates in beta form to OEM
| system manufacturers and system software vendors. They are being
| readied for production release, and will be delivered to consumers
| and IT Professionals in the coming weeks.
This bulletin will be updated once the Intel microcode updates are
available. No microcode update is necessary for AMD processors.

Credits
========

See the original Xen Security Advisory.

References
===========

[1] https://xenbits.xen.org/xsa/advisory-263.html
[2] https://github.com/QubesOS/qubes-secpack/blob/master/QSBs/qsb-037-2018.txt
[3] https://www.intel.com/content/www/us/en/architecture-and-technology/facts-about-side-channel-analysis-and-intel-products.html

--
The Qubes Security Team
https://www.qubes-os.org/security/
Comment on Xen Project 4.10.1 Available by GeorgeBray_1986
https://blog.xenproject.org/2018/05/03/xen-project-4-10-1-available/#comment-512

Thank you for update! A lot of bug was fixed.
Comment on Xen Project Announces Schedule for its Annual Developer and Design Summit by GeorgeBray_1986
https://blog.xenproject.org/2018/05/03/xen-project-announces-schedule-for-its-annual-developer-and-design-summi/#comment-511

Nice event! Good luck!
Comment on Xen Project 4.10.1 Available by fbifido
https://blog.xenproject.org/2018/05/03/xen-project-4-10-1-available/#comment-515

Where do I see what's new, what's fix?
Update for QSB #40: Information leaks due to processor speculative store bypass (XSA-263)
https://www.qubes-os.org/news/2018/06/13/qsb-40-update/

Dear Qubes Community,

We have updated Qubes Security Bulletin (QSB) #40: Information leaks due
to processor speculative store bypass (XSA-263). The text of the main
changes are reproduced below. For the full text, please see the complete
QSB in the qubes-secpack:

View QSB #40 in the qubes-secpack:

https://github.com/QubesOS/qubes-secpack/blob/master/QSBs/qsb-040-2018.txt

Learn about the qubes-secpack, including how to obtain, verify, and read
it:

https://www.qubes-os.org/security/pack/

View all past QSBs:

https://www.qubes-os.org/security/bulletins/

View XSA-263 in the XSA Tracker:

https://www.qubes-os.org/security/xsa/#263

Changelog
==========

2018-05-24: Original QSB published
2018-06-11: Updated and clarified Patching section

Patching
=========

The mitigation for this issue is called called "Speculative Store Bypass
Disable" (SSBD). For Intel processors, SSBD requires both a software
update and a CPU microcode update. For AMD processors, a software update
alone is sufficient; no microcode update is necessary. The packages
described below provide the necessary software updates for SSBD. On
2018-05-23, Intel Corporation announced that microcode updates would be
available soon [3]:

| Variant 3a is mitigated in the same processor microcode updates as
| Variant 4, and Intel has released these updates in beta form to OEM
| system manufacturers and system software vendors. They are being
| readied for production release, and will be delivered to consumers
| and IT Professionals in the coming weeks.

However, as of 2018-06-11, we are not aware of any available microcode
updates that address this issue for Intel processors. This bulletin will
be updated once the Intel microcode updates are available.

There are several important things to note about SSBD:

1. On both Intel and AMD processors, SSBD is globally disabled by
default. If the user wishes to enable SSBD globally, the user must do
so manually with the Xen boot option `spec-ctrl=ssbd=true`. However,
enabling this option carries a performance penalty.

2. We concur with the analysis in XSA-263 that this vulnerability
presents minimal risk to Xen itself and minimal risk of inter-guest
attacks. Therefore, we believe that proper compartmentalization is
sufficient for Qubes users to mitigate this issue without having to
enable SSBD globally.

3. For Intel (but not AMD) processors, SSBD can be enabled locally by
Xen guests without the user having to manually enable it globally.

4. For AMD (but not Intel) processors, SSBD cannot be enabled locally by
Xen guests. The user must manually enable it globally for it to have
any effect at all.

5. The guest kernel determines whether SSBD is automatically enabled for
guests on systems with Intel processors. As of 2018-06-11, the
kernels we currently offer in our repositories do not enable SSBD.
QSB #41: Speculative register leakage from lazy FPU context switching (XSA-267)
https://www.qubes-os.org/news/2018/06/13/qsb-41/

Dear Qubes Community,

We have just published Qubes Security Bulletin (QSB) #41: Speculative
register leakage from lazy FPU context switching (XSA-267). The text of
this QSB is reproduced below. This QSB and its accompanying signatures
will always be available in the Qubes Security Pack (qubes-secpack).

View QSB #41 in the qubes-secpack:

https://github.com/QubesOS/qubes-secpack/blob/master/QSBs/qsb-041-2018.txt

Learn about the qubes-secpack, including how to obtain, verify, and read
it:

https://www.qubes-os.org/security/pack/

View all past QSBs:

https://www.qubes-os.org/security/bulletins/

View XSA-267 in the XSA Tracker:

https://www.qubes-os.org/security/xsa/#267

---===[ Qubes Security Bulletin #41 ]===---

2018-06-13


Speculative register leakage from lazy FPU context switching (XSA-267)

Summary
========

On 2018-06-13, the Xen Security Team published Xen Security Advisory
267 (CVE-2018-3665 / XSA-267) [1] with the following denoscription:

| x86 has a hardware mechanism for lazy FPU context switching. On a
| task switch, %cr0.ts (Task Switched) gets set, and the next
| instruction to touch floating point state raises an #NM (No Math,
| later known as Device Not Available) exception.
|
| Traditionally, FPU state has been large in comparison to available
| bandwidth (and therefore slow to switch) and not used as frequently as
| cpu tasks tend to switch. This mechanism allows the OS to only switch
| FPU when necessary, which in turn increases performance.
|
| Some CPUs however speculate past an #NM exception, allowing register
| content to be leaked by a side-channel.
|
| An attacker can read x87/MMX/SSE/AVX/AVX-512 register state belonging
| to another vCPU previously scheduled on the same processor. This can
| be state belonging a different guest, or state belonging to a
| different thread inside the same guest.

This is yet another CPU hardware bug related to speculative execution.

Patching
=========

To resolve this issue, the Xen Project has provided patches disabling
lazy FPU context switching on affected systems.

The specific packages that resolve the problems discussed in this
bulletin are as follows:

For Qubes 3.2:
- Xen packages, version 4.6.6-42

For Qubes 4.0:
- Xen packages, version 4.8.3-9

The packages are to be installed in dom0 via the Qubes VM Manager or via
the qubes-dom0-update command as follows:

For updates from the stable repository (not immediately available):
$ sudo qubes-dom0-update

For updates from the security-testing repository:
$ sudo qubes-dom0-update --enablerepo=qubes-dom0-security-testing

A system restart will be required afterwards.

These packages will migrate from the security-testing repository to the
current (stable) repository over the next two weeks after being tested
by the community.

If you use Anti Evil Maid, you will need to reseal your secret
passphrase to new PCR values, as PCR18+19 will change due to the new
Xen binaries.

Credits
========

See the original Xen Security Advisory.

References
===========

[1] https://xenbits.xen.org/xsa/advisory-267.html

--
The Qubes Security Team
https://www.qubes-os.org/security/
Qubes Canary #16
https://www.qubes-os.org/news/2018/06/14/canary-16/

Dear Qubes Community,

We have published Qubes Canary #16. The text of this canary is
reproduced below. This canary and its accompanying signatures will
always be available in the Qubes Security Pack (qubes-secpack).

View Qubes Canary #16 in the qubes-secpack:

https://github.com/QubesOS/qubes-secpack/blob/master/canaries/canary-016-2018.txt

Learn about the qubes-secpack, including how to obtain, verify, and read
it:

https://www.qubes-os.org/security/pack/

View all past canaries:

https://www.qubes-os.org/security/canaries/

---===[ Qubes Canary #16 ]===---


Statements
-----------

The Qubes core developers who have digitally signed this file [1]
state the following:

1. The date of issue of this canary is June 14, 2018.

2. There have been 41 Qubes Security Bulletins published so far.

3. The Qubes Master Signing Key fingerprint is:

427F 11FD 0FAA 4B08 0123 F01C DDFA 1A3E 3687 9494

4. No warrants have ever been served to us with regard to the Qubes OS
Project (e.g. to hand out the private signing keys or to introduce
backdoors).

5. We plan to publish the next of these canary statements in the first
two weeks of October 2018. Special note should be taken if no new canary
is published by that time or if the list of statements changes without
plausible explanation.

Special announcements
----------------------

None.

Disclaimers and notes
----------------------

We would like to remind you that Qubes OS has been designed under the
assumption that all relevant infrastructure is permanently
compromised. This means that we assume NO trust in any of the servers
or services which host or provide any Qubes-related data, in
particular, software updates, source code repositories, and Qubes ISO
downloads.

This canary scheme is not infallible. Although signing the declaration
makes it very difficult for a third party to produce arbitrary
declarations, it does not prevent them from using force or other
means, like blackmail or compromising the signers' laptops, to coerce
us to produce false declarations.

The news feeds quoted below (Proof of freshness) serves to demonstrate
that this canary could not have been created prior to the date stated.
It shows that a series of canaries was not created in advance.

This declaration is merely a best effort and is provided without any
guarantee or warranty. It is not legally binding in any way to
anybody. None of the signers should be ever held legally responsible
for any of the statements made here.

Proof of freshness
-------------------

$ date -R -u
Thu, 14 Jun 2018 07:47:57 +0000

$ feedstail -1 -n5 -f '{noscript}' -u https://www.spiegel.de/international/index.rss
Rise of the Autocrats: Liberal Democracy Is Under Attack
Economic Trumpism: U.S. President Makes Life Tough for German Companies
The G-7 Fiasco: It's Time to Isolate Donald Trump
Finance Minister Olaf Scholz: 'Germany Has a Special Responsibility'
Trapped in the Past: Increasing Headwinds for Angela Merkel

$ feedstail -1 -n5 -f '{noscript}' -u https://rss.nytimes.com/services/xml/rss/nyt/World.xml
Trump Sees End to North Korea Threat Despite Unclear Path Forward
Humanitarian Crisis Worsens in Yemen After Attack on Port
Who Is Behind Trump’s Links to Arab Princes? A Billionaire Friend
Trump-Kim Summit Creates New Anxieties for Asian Allies
New Delhi Dispatch: The Personal Wake-Up Call to Prayers, a Ramadan Tradition, Is Endangered

$ feedstail -1 -n5 -f '{noscript}' -u https://feeds.bbci.co.uk/news/world/rss.xml
North Korea sanctions remain until complete denuclearisation, says US
London Breed becomes San Francisco's first black female mayor
Chile police raid Catholic Church offices amid sex abuse scandal
Yemen war: Fighting rages over vital port of Hudaydah
Apple to close iPhone security loophole used by police

$ feedstail -1 -n5 -f '{noscript}' -u http://feeds.reuters.com/reuters/worldnews
Pompeo says North Korea sanctions to remain until complete denuclearization
Saudi-led coalition keeps up Hodeidah assault before U.N. meeting
Italy still waiting for apology from France's Macron: deputy PM
In boost for Australian PM, right-wing party loses power to block his bills
'Where is Singapore?': Trump-Kim summit a PR coup for tiny city-state

$ curl -s 'https://blockchain.info/blocks/?format=json'

$ python3 -c 'import sys, json; print(json.load(sys.stdin)['\''blocks'\''][10]['\''hash'\''])'
000000000000000000212905769ee24bbb82122b44d6413974673a122a7cdaa8

Footnotes
----------

[1] This file should be signed in two ways: (1) via detached PGP
signatures by each of the signers, distributed together with this
canary in the qubes-secpack.git repo, and (2) via digital signatures
on the corresponding qubes-secpack.git repo tags. [2]

[2] Don't just trust the contents of this file blindly! Verify the
digital signatures!
Marek Marczykowski-Górecki to speak at the Xen Developer and Design Summit 2018
https://www.qubes-os.org/news/2018/06/17/marek-marczykowski-gorecki-xen-summit-2018/

Marek Marczykowski-Górecki (https://www.qubes-os.org/team/#marek-marczykowski-g%C3%B3recki) will be speaking at this year’s Xen Developer and
Design Summit (https://www.lfasiallc.com/events/xensummit2018/). The summit will take place in Nanjing Jiangning, China from June
20–22, 2018. Marek will present on linux-based device model stubdomains in
Qubes OS. For more information about the summit, please see the announcement on
the Xen blog (https://blog.xenproject.org/2018/05/03/xen-project-announces-schedule-for-its-annual-developer-and-design-summi/).
Improving the Stealthiness of Virtual Machine Introspection on Xen
https://blog.xenproject.org/2018/06/21/improving-the-stealthiness-of-virtual-machine-introspection-on-xen/

This blog post comes from Stewart Sentanoe of the University of Passau. Stewart is an Assistant Professor of Security in Information Systems at the Faculty of Computer Science and Mathematics. He was recently a Google Summer of Code Intern working on the Honeynet Project.  Project Introduction Virtual Machine Introspection Virtual Machine Introspection (VMI) is the process of examining and […]
XSA-264, XSA-265, and XSA-266 do not affect the security of Qubes OS
https://www.qubes-os.org/news/2018/06/27/xsa-264-265-266-qubes-not-affected/

The Xen Project has published Xen Security Advisories 264, 265 and 266
(XSA-264, XSA-265, and XSA-266, respectively). These XSAs do not
affect the security of Qubes OS, and no user action is necessary.

These XSAs have been added to the XSA Tracker (https://www.qubes-os.org/security/xsa/):

https://www.qubes-os.org/security/xsa/#264
https://www.qubes-os.org/security/xsa/#265
https://www.qubes-os.org/security/xsa/#266
Qubes OS pinned «XSA-264, XSA-265, and XSA-266 do not affect the security of Qubes OS https://www.qubes-os.org/news/2018/06/27/xsa-264-265-266-qubes-not-affected/ The Xen Project has published Xen Security Advisories 264, 265 and 266 (XSA-264, XSA-265, and XSA-266, respectively).…»
Comment on Stealthy monitoring with Xen altp2m by Improving the Stealthiness of Virtual Machine Introspection on Xen | Xen Project Blog
https://blog.xenproject.org/2016/04/13/stealthy-monitoring-with-xen-altp2m/#comment-518

[…] There are two ways to set a breakpoint implemented by DRAKVUF using INT3 (0xCC opcode) and Xen altp2m. […]
Xen Project 4.7.6 is available!
https://blog.xenproject.org/2018/07/09/xen-project-4-7-6-is-available/

I am pleased to announce the release of the Xen 4.7.6. Xen Project maintenance releases are released in line with our Maintenance Release Policy. We recommend that all users of the 4.7 stable series update to the latest point release. The release is available from its git repositories xenbits.xen.org/gitweb/?p=xen.git;a=shortlog;h=refs/heads/stable-4.7 (tag RELEASE-4.7.6) or from the Xen […]
Qubes OS pinned «Xen Project 4.7.6 is available! https://blog.xenproject.org/2018/07/09/xen-project-4-7-6-is-available/ I am pleased to announce the release of the Xen 4.7.6. Xen Project maintenance releases are released in line with our Maintenance Release Policy. We recommend…»
What’s New in the Xen Project Hypervisor 4.11
https://blog.xenproject.org/2018/07/10/whats-new-in-the-xen-project-hypervisor-4-11/

I am pleased to announce the release of the Xen Project Hypervisor 4.11. One of our long-term development goals since the introduction of Xen Project Hypervisor 4.8 has been to create a cleaner architecture for core technology, less code and a smaller computing base for security and performance. The Xen 4.11 release has followed this […]
Qubes OS pinned «What’s New in the Xen Project Hypervisor 4.11 https://blog.xenproject.org/2018/07/10/whats-new-in-the-xen-project-hypervisor-4-11/ I am pleased to announce the release of the Xen Project Hypervisor 4.11. One of our long-term development goals since the introduction…»
Comment on What’s New in the Xen Project Hypervisor 4.11 by ?Re-engineering Xen: The important open-source hypervisor gets remodeled - IT AND US
https://blog.xenproject.org/2018/07/10/whats-new-in-the-xen-project-hypervisor-4-11/#comment-521

[…] VM products from Citrix, Huawei, Inspur, and Oracle. But, with the release of its latest edition, Xen Project Hypervisor 4.11, there are major changes under the […]
Comment on What’s New in the Xen Project Hypervisor 4.11 by ?Re-engineering Xen: The important open-source hypervisor gets remodeled | BuzzNews10
https://blog.xenproject.org/2018/07/10/whats-new-in-the-xen-project-hypervisor-4-11/#comment-522

[…] from Citrix, Huawei, Inspur, and Oracle. However, with the discharge of its newest version, Xen Project Hypervisor 4.11, there are main adjustments underneath the […]
Comment on What’s New in the Xen Project Hypervisor 4.11 by ?Re-engineering Xen: The important open-source hypervisor gets remodeled | Longevity Technology
https://blog.xenproject.org/2018/07/10/whats-new-in-the-xen-project-hypervisor-4-11/#comment-523

[…] VM products from Citrix, Huawei, Inspur, and Oracle. But, with the release of its latest edition, Xen Project Hypervisor 4.11, there are major changes under the […]