Protect yourself against future threats.
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA256
===========================================================================
AUSCERT External Security Bulletin Redistribution
ESB-2021.0263
IRQ vector leak on x86
22 January 2021
===========================================================================
AusCERT Security Bulletin Summary
---------------------------------
Product: Xen
Publisher: Xen
Operating System: Linux variants
Virtualisation
Impact/Access: Denial of Service -- Existing Account
Resolution: Patch/Upgrade
Original Bulletin:
http://xenbits.xen.org/xsa/advisory-360.html
- --------------------------BEGIN INCLUDED TEXT--------------------
- -----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA256
Xen Security Advisory XSA-360
IRQ vector leak on x86
ISSUE DESCRIPTION
=================
A x86 HVM guest with PCI pass through devices can force the allocation
of all IDT vectors on the system by rebooting itself with MSI or MSI-X
capabilities enabled and entries setup.
Such reboots will leak any vectors used by the MSI(-X) entries that the
guest might had enabled, and hence will lead to vector exhaustion on the
system, not allowing further PCI pass through devices to work properly.
IMPACT
======
HVM guests with PCI pass through devices can mount a Denial of Service (DoS)
attack affecting the pass through of PCI devices to other guests or the
hardware domain. In the latter case this would affect the entire host.
VULNERABLE SYSTEMS
==================
Xen versions 4.12.3, 4.12.4, and all versions from 4.13.1 onwards are
vulnerable. Xen version 4.13.0 and all versions up to 4.12.2 are not
affected.
Only x86 systems running HVM guests with PCI pass through devices are
vulnerable.
MITIGATION
==========
Not running HVM guests with PCI pass through devices will avoid the
vulnerability. Note that even non-malicious guests can trigger this
vulnerability as part of normal operation.
RESOLUTION
==========
Applying the appropriate attached patch resolves this issue.
Note that patches for released versions are generally prepared to
apply to the stable branches, and may not apply cleanly to the most
recent release tarball. Downstreams are encouraged to update to the
tip of the stable branch before applying these patches.
xsa360.patch xen-unstable
xsa360-4.14.patch Xen 4.14 - 4.12
$ sha256sum xsa360*
c874ad2b9edb0791ac975735306d055b1916f4acbc59e6f1550fbf33223d6106 xsa360.meta
592f3afda63777d31844e0e34d85fbe387a62d59fa7903ee19b22a98fba68894 xsa360.patch
809515011efb781a2a8742e9acfd76412d3920c2d4142bb187588cd36f77383e xsa360-4.14.patch
$
CREDITS
=======
This issue was discovered by James McCoy, debugged in combination with
Samuel Verschelde of Vates, and recognised as a security issue by Roger
Pau Monne of Citrix.
NOTE REGARDING LACK OF EMBARGO
==============================
This was reported and debugged publicly, before the security
implications were apparent.
- -----BEGIN PGP SIGNATURE-----
iQFABAEBCAAqFiEEI+MiLBRfRHX6gGCng/4UyVfoK9kFAmAJixQMHHBncEB4ZW4u
b3JnAAoJEIP+FMlX6CvZh4cH/RyA5POGYEJEj4jHUFK+UmT08Bo6igUBMyJSvAJs
T81eb35E2E2I8P35L7q8OOuLIGPWnTXOGPRnwizr2YF7UhmMm/773q5ellShUBgm
SHtYl+btRaAp6gXB1PhgiETN3EH3aRgn89YBAQmg3U4Zb1RUiB2P2x6pVEGjMfBw
Ks3Zj/ElCtfJcBA6xerNNLuqhwamueCEukw5b8eEHnop+y7TuLordpGGMybpQctx
m04lp7zuJDAeshf47wlMQps79Ysx72CaThVKe/9A09z/c2mcR3m+NbieP7PJPggr
n1I6QEaSUuapszkj+lC/L05tiyHdjXkoNAHwtdPr8jKtbKo=
=YdXv
- -----END PGP SIGNATURE-----
- --------------------------END INCLUDED TEXT--------------------
You have received this e-mail bulletin as a result of your organisation's
registration with AusCERT. The mailing list you are subscribed to is
maintained within your organisation, so if you do not wish to continue
receiving these bulletins you should contact your local IT manager. If
you do not know who that is, please send an email to auscert@auscert.org.au
and we will forward your request to the appropriate person.
NOTE: Third Party Rights
This security bulletin is provided as a service to AusCERT's members. As
AusCERT did not write the document quoted above, AusCERT has had no control
over its content. The decision to follow or act on information or advice
contained in this security bulletin is the responsibility of each user or
organisation, and should be considered in accordance with your organisation's
site policies and procedures. AusCERT takes no responsibility for consequences
which may arise from following or acting on information or advice contained in
this security bulletin.
NOTE: This is only the original release of the security bulletin. It may
not be updated when updates to the original are made. If downloading at
a later date, it is recommended that the bulletin is retrieved directly
from the author's website to ensure that the information is still current.
Contact information for the authors of the original document is included
in the Security Bulletin above. If you have any questions or need further
information, please contact them directly.
Previous advisories and external security bulletins can be retrieved from:
https://www.auscert.org.au/bulletins/
===========================================================================
Australian Computer Emergency Response Team
The University of Queensland
Brisbane
Qld 4072
Internet Email: auscert@auscert.org.au
Facsimile: (07) 3365 7031
Telephone: (07) 3365 4417 (International: +61 7 3365 4417)
AusCERT personnel answer during Queensland business hours
which are GMT+10:00 (AEST).
On call after hours for member emergencies only.
===========================================================================
-----BEGIN PGP SIGNATURE-----
Comment: http://www.auscert.org.au/render.html?it=1967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=7+vJ
-----END PGP SIGNATURE-----