oss-sec mailing list archives

Re: Xen Security Advisory 204 - x86: Mishandling of SYSCALL singlestep during emulation


From: <cve-assign () mitre org>
Date: Mon, 19 Dec 2016 11:34:56 -0500

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA256

                    Xen Security Advisory XSA-204

Xen wrongly raised the exception based on the flags at the start of
the instruction.

Guest userspace which can invoke the instruction emulator can use this
flaw to escalate its privilege to that of the guest kernel.

A 64-bit guest kernel which uses an IST for #DB handling will most likely
mitigate the issue, but will have a single unexpected #DB exception
frame to deal with. This in practice means that Linux is not
vulnerable.

Use CVE-2016-10013.

- -- 
CVE Assignment Team
M/S M300, 202 Burlington Road, Bedford, MA 01730 USA
[ A PGP key is available for encrypted communications at
  http://cve.mitre.org/cve/request_id.html ]
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1
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=KJsh
-----END PGP SIGNATURE-----


Current thread: