Protect yourself against future threats.
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AUSCERT External Security Bulletin Redistribution
ESB-2018.0467
xen security update
16 February 2018
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AusCERT Security Bulletin Summary
---------------------------------
Product: xen
Publisher: Debian
Operating System: Debian GNU/Linux 9
Impact/Access: Increased Privileges -- Existing Account
Denial of Service -- Existing Account
Resolution: Patch/Upgrade
CVE Names: CVE-2017-17566 CVE-2017-17565 CVE-2017-17564
CVE-2017-17563
Reference: ESB-2018.0462
Original Bulletin:
http://www.debian.org/security/2018/dsa-4112
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Debian Security Advisory DSA-4112-1 security@debian.org
https://www.debian.org/security/ Moritz Muehlenhoff
February 14, 2018 https://www.debian.org/security/faq
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Package : xen
CVE ID : CVE-2017-17563 CVE-2017-17564 CVE-2017-17565
CVE-2017-17566
Multiple vulnerabilities have been discovered in the Xen hypervisor:
CVE-2017-17563
Jan Beulich discovered that an incorrect reference count overflow
check in x86 shadow mode may result in denial of service or
privilege escalation.
CVE-2017-17564
Jan Beulich discovered that improper x86 shadow mode reference count
error handling may result in denial of service or privilege
escalation.
CVE-2017-17565
Jan Beulich discovered that an incomplete bug check in x86 log-dirty
handling may result in denial of service.
CVE-2017-17566
Jan Beulich discovered that x86 PV guests may gain access to
internally used pages which could result in denial of service or
potential privilege escalation.
In addition this update ships the "Comet" shim to address the Meltdown
class of vulnerabilities for guests with legacy PV kernels. In addition,
the package provides the "Xen PTI stage 1" mitigation which is built-in
and enabled by default on Intel systems, but can be disabled with
`xpti=false' on the hypervisor command line (It does not make sense to
use both xpti and the Comet shim.)
Please refer to the following URL for more details on how to configure
individual mitigation strategies:
https://xenbits.xen.org/xsa/advisory-254.html
Additional information can also be found in README.pti and README.comet.
For the stable distribution (stretch), these problems have been fixed in
version 4.8.3+comet2+shim4.10.0+comet3-1+deb9u4.1.
We recommend that you upgrade your xen packages.
For the detailed security status of xen please refer to
its security tracker page at:
https://security-tracker.debian.org/tracker/xen
Further information about Debian Security Advisories, how to apply
these updates to your system and frequently asked questions can be
found at: https://www.debian.org/security/
Mailing list: debian-security-announce@lists.debian.org
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