CVE - CVE-2019-18425

CVE-ID
CVE-2019-18425	Learn more at National Vulnerability Database (NVD) • CVSS Severity Rating • Fix Information • Vulnerable Software Versions • SCAP Mappings • CPE Information
Description
An issue was discovered in Xen through 4.12.x allowing 32-bit PV guest OS users to gain guest OS privileges by installing and using descriptors. There is missing descriptor table limit checking in x86 PV emulation. When emulating certain PV guest operations, descriptor table accesses are performed by the emulating code. Such accesses should respect the guest specified limits, unless otherwise guaranteed to fail in such a case. Without this, emulation of 32-bit guest user mode calls through call gates would allow guest user mode to install and then use descriptors of their choice, as long as the guest kernel did not itself install an LDT. (Most OSes don't install any LDT by default). 32-bit PV guest user mode can elevate its privileges to that of the guest kernel. Xen versions from at least 3.2 onwards are affected. Only 32-bit PV guest user mode can leverage this vulnerability. HVM, PVH, as well as 64-bit PV guests cannot leverage this vulnerability. Arm systems are unaffected.
References
Note: References are provided for the convenience of the reader to help distinguish between vulnerabilities. The list is not intended to be complete.
BUGTRAQ:20200114 [SECURITY] [DSA 4602-1] xen security update URL:https://seclists.org/bugtraq/2020/Jan/21 DEBIAN:DSA-4602 URL:https://www.debian.org/security/2020/dsa-4602 FEDORA:FEDORA-2019-376ec5c107 URL:https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/I5WWPW4BSZDDW7VHU427XTVXV7ROOFFW/ FEDORA:FEDORA-2019-865bb16900 URL:https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/2BQKX7M2RHCWDBKNPX4KEBI3MJIH6AYZ/ FEDORA:FEDORA-2019-cbb732f760 URL:https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/IZYATWNUGHRBG6I3TC24YHP5Y3J7I6KH/ GENTOO:GLSA-202003-56 URL:https://security.gentoo.org/glsa/202003-56 MISC:http://xenbits.xen.org/xsa/advisory-298.html MLIST:[oss-security] 20191031 Xen Security Advisory 298 v3 (CVE-2019-18425) - missing descriptor table limit checking in x86 PV emulation URL:http://www.openwall.com/lists/oss-security/2019/10/31/2 SUSE:openSUSE-SU-2019:2506 URL:http://lists.opensuse.org/opensuse-security-announce/2019-11/msg00037.html
Assigning CNA
MITRE Corporation
Date Record Created
20191024	Disclaimer: The record creation date may reflect when the CVE ID was allocated or reserved, and does not necessarily indicate when this vulnerability was discovered, shared with the affected vendor, publicly disclosed, or updated in CVE.
Phase (Legacy)
Assigned (20191024)
Votes (Legacy)

Comments (Legacy)

Proposed (Legacy)
N/A
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