CVE-2019-18425
published 2019-10-31CVE-2019-18425: 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…
PriorityP353critical9.8CVSS 3.1
AVNACLPRNUINSUCHIHAH
EPSS
2.55%
83.2th percentile
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.
Affected
12 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| debian | debian_linux | — | — |
| debian | debian_linux | — | — |
| debian | xen | < xen 4.11.3+24-g14b62ab3e5-1 (bookworm) | xen 4.11.3+24-g14b62ab3e5-1 (bookworm) |
| fedoraproject | fedora | — | — |
| fedoraproject | fedora | — | — |
| fedoraproject | fedora | — | — |
| opensuse | leap | — | — |
| xen | xen | <= 4.12.1 | — |
| xen | xen | >= 0 < 4.11.3+24-g14b62ab3e5-1 | 4.11.3+24-g14b62ab3e5-1 |
| xen | xen | >= 0 < 4.11.3+24-g14b62ab3e5-1 | 4.11.3+24-g14b62ab3e5-1 |
| xen | xen | >= 0 < 4.11.3+24-g14b62ab3e5-1 | 4.11.3+24-g14b62ab3e5-1 |
| xen | xen | >= 0 < 4.11.3+24-g14b62ab3e5-1 | 4.11.3+24-g14b62ab3e5-1 |
CVSS provenance
nvdv3.19.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
nvdv2.09.3CRITICALAV:N/AC:M/Au:N/C:C/I:C/A:C
osv9.8CRITICAL
vendor_debian9.8CRITICAL
vendor_redhat9.8CRITICAL
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Red Hat
xen: missing descriptor table limit checking in x86 PV emulation leading to privilege escalation
vendor_redhat·2019-10-31·CVSS 9.8
CVE-2019-18425 [CRITICAL] CWE-250 xen: missing descriptor table limit checking in x86 PV emulation leading to privilege escalation
xen: missing descriptor table limit checking in x86 PV emulation leading to privilege escalation
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
Debian
CVE-2019-18425: xen - An issue was discovered in Xen through 4.12.x allowing 32-bit PV guest OS users ...
vendor_debian·2019·CVSS 9.8
CVE-2019-18425 [CRITICAL] CVE-2019-18425: xen - An issue was discovered in Xen through 4.12.x allowing 32-bit PV guest OS users ...
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
GHSA
GHSA-wfcx-xxhx-657g: An issue was discovered in Xen through 4
ghsa_unreviewed·2022-05-24
CVE-2019-18425 [HIGH] CWE-269 GHSA-wfcx-xxhx-657g: An issue was discovered in Xen through 4
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
OSV
CVE-2019-18425: An issue was discovered in Xen through 4
osv·2019-10-31·CVSS 9.8
CVE-2019-18425 [CRITICAL] CVE-2019-18425: An issue was discovered in Xen through 4
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
No detection rules found.
No public exploits indexed.
Bugzilla
CVE-2019-18425 xen: missing descriptor table limit checking in x86 PV emulation leading to privilege escalation [fedora-all]
bugzilla·2019-11-12·CVSS 9.8
CVE-2019-18425 [CRITICAL] CVE-2019-18425 xen: missing descriptor table limit checking in x86 PV emulation leading to privilege escalation [fedora-all]
CVE-2019-18425 xen: missing descriptor table limit checking in x86 PV emulation leading to privilege escalation [fedora-all]
This is an automatically created tracking bug! It was created to ensure
that one or more security vulnerabilities are fixed in affected versions
of fedora-all.
For comments that are specific to the vulnerability please use bugs filed
against the "Security Response" product referenced in the "Blocks" field.
For more information see:
http://fedoraproject.org/wiki/Security/TrackingBugs
When submitting as an update, use the fedpkg template provided in the next
comment(s). This will include the bug IDs of this tracking bug as well as
the relevant top-level CVE bugs.
Please also mention the CVE IDs being fixed in the RPM changelog and the
fedpkg commit message.
NOTE:
Bugzilla
CVE-2019-18425 xen: missing descriptor table limit checking in x86 PV emulation leading to privilege escalation
bugzilla·2019-11-12·CVSS 9.8
CVE-2019-18425 [CRITICAL] CVE-2019-18425 xen: missing descriptor table limit checking in x86 PV emulation leading to privilege escalation
CVE-2019-18425 xen: missing descriptor table limit checking in x86 PV emulation leading to privilege escalation
When emulating certain PV guest operations, descriptor table accesses are performed by the emulating code. Such accesses should respect the guest specified limits. 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.
Only 32-bit PV guest user mode can leverage this vulnerability.
Upstream advisory and patches:
http://xenbits.xen.org/xsa/advisory-298.html
Discussion:
Created xen tracking bugs for this issue:
Affects: fedora-all [bug 1771341]
---
External References:
http://xenbits.xen.org/xsa/advisory-298.html
http://lists.opensuse.org/opensuse-security-announce/2019-11/msg00037.htmlhttp://www.openwall.com/lists/oss-security/2019/10/31/2http://xenbits.xen.org/xsa/advisory-298.htmlhttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2BQKX7M2RHCWDBKNPX4KEBI3MJIH6AYZ/https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/I5WWPW4BSZDDW7VHU427XTVXV7ROOFFW/https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/IZYATWNUGHRBG6I3TC24YHP5Y3J7I6KH/https://seclists.org/bugtraq/2020/Jan/21https://security.gentoo.org/glsa/202003-56https://www.debian.org/security/2020/dsa-4602http://lists.opensuse.org/opensuse-security-announce/2019-11/msg00037.htmlhttp://www.openwall.com/lists/oss-security/2019/10/31/2http://xenbits.xen.org/xsa/advisory-298.htmlhttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2BQKX7M2RHCWDBKNPX4KEBI3MJIH6AYZ/https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/I5WWPW4BSZDDW7VHU427XTVXV7ROOFFW/https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/IZYATWNUGHRBG6I3TC24YHP5Y3J7I6KH/https://seclists.org/bugtraq/2020/Jan/21https://security.gentoo.org/glsa/202003-56https://www.debian.org/security/2020/dsa-4602
2019-10-31
Published