An issue was discovered in Xen through 4.12.x allowing ARM guest OS users to cause a denial of service or gain privileges by leveraging the erroneous enabling of interrupts. Interrupts are unconditionally unmasked in exception handlers. When an exception occurs on an ARM system which is handled without changing processor level, some interrupts are unconditionally enabled during exception entry. So exceptions which occur when interrupts are masked will effectively unmask the interrupts. A malicious guest might contrive to arrange for critical Xen code to run with interrupts erroneously enabled. This could lead to data corruption, denial of service, or possibly even privilege escalation. However a precise attack technique has not been identified.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - An issue was discovered in Xen through 4.12.x allowing ARM guest OS users to cause a denial of service or     gain privileges by leveraging the erroneous enabling of interrupts. Interrupts are unconditionally     unmasked in exception handlers. When an exception occurs on an ARM system which is handled without     changing processor level, some interrupts are unconditionally enabled during exception entry. So     exceptions which occur when interrupts are masked will effectively unmask the interrupts. A malicious     guest might contrive to arrange for critical Xen code to run with interrupts erroneously enabled. This     could lead to data corruption, denial of service, or possibly even privilege escalation. However a precise     attack technique has not been identified. (CVE-2019-18422)

Note that Nessus relies on the presence of the package as reported by the vendor.

There are packages installed that are affected by multiple vulnerabilities referenced in the following CVEs:

  - 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. (CVE-2019-18425)

  - Improper invalidation for page table updates by a virtual guest operating system for multiple Intel(R)
    Processors may allow an authenticated user to potentially enable denial of service of the host system via
    local access. (CVE-2018-12207)

  - TSX Asynchronous Abort condition on some CPUs utilizing speculative execution may allow an authenticated
    user to potentially enable information disclosure via a side channel with local access. (CVE-2019-11135)

  - An issue was discovered in Xen through 4.12.x allowing x86 PV guest OS users to gain host OS privileges by
    leveraging race conditions in pagetable promotion and demotion operations. There are issues with
    restartable PV type change operations. To avoid using shadow pagetables for PV guests, Xen exposes the
    actual hardware pagetables to the guest. In order to prevent the guest from modifying these page tables
    directly, Xen keeps track of how pages are used using a type system; pages must be "promoted" before being
    used as a pagetable, and "demoted" before being used for any other type. Xen also allows for "recursive"
    promotions: i.e., an operating system promoting a page to an L4 pagetable may end up causing pages to be
    promoted to L3s, which may in turn cause pages to be promoted to L2s, and so on. These operations may take
    an arbitrarily large amount of time, and so must be re-startable. Unfortunately, making recursive
    pagetable promotion and demotion operations restartable is incredibly complicated, and the code contains
    several races which, if triggered, can cause Xen to drop or retain extra type counts, potentially allowing
    guests to get write access to in-use pagetables. A malicious PV guest administrator may be able to
    escalate their privilege to that of the host. All x86 systems with untrusted PV guests are vulnerable. HVM
    and PVH guests cannot exercise this vulnerability. (CVE-2019-18421)

  - An issue was discovered in Xen through 4.12.x allowing ARM guest OS users to cause a denial of service or
    gain privileges by leveraging the erroneous enabling of interrupts. Interrupts are unconditionally
    unmasked in exception handlers. When an exception occurs on an ARM system which is handled without
    changing processor level, some interrupts are unconditionally enabled during exception entry. So
    exceptions which occur when interrupts are masked will effectively unmask the interrupts. A malicious
    guest might contrive to arrange for critical Xen code to run with interrupts erroneously enabled. This
    could lead to data corruption, denial of service, or possibly even privilege escalation. However a precise
    attack technique has not been identified. (CVE-2019-18422)

Multiple vulnerabilities have been discovered in the Xen hypervisor, which could result in denial of service, guest-to-host privilege escalation or information leaks.

In addition this update provides mitigations for the 'TSX Asynchronous Abort'speculative side channel attack. For additional information please refer to https://xenbits.xen.org/xsa/advisory-305.html

This update for xen fixes the following issues :

CVE-2019-19581: Fixed a potential out of bounds on 32-bit Arm (bsc#1158003 XSA-307).

CVE-2019-19582: Fixed a potential infinite loop when x86 accesses to bitmaps with a compile time known size of 64 (bsc#1158003 XSA-307).

CVE-2019-19583: Fixed improper checks which could have allowed HVM/PVH guest userspace code to crash the guest,leading to a guest denial of service (bsc#1158004 XSA-308).

CVE-2019-19578: Fixed an issue where a malicious or buggy PV guest could have caused hypervisor crash resulting in denial of service affecting the entire host (bsc#1158005 XSA-309).

CVE-2019-19580: Fixed a privilege escalation where a malicious PV guest administrator could have been able to escalate their privilege to that of the host (bsc#1158006 XSA-310).

CVE-2019-19577: Fixed an issue where a malicious guest administrator could have caused Xen to access data structures while they are being modified leading to a crash (bsc#1158007 XSA-311).

CVE-2019-19579: Fixed a privilege escaltion where an untrusted domain with access to a physical device can DMA into host memory (bsc#1157888 XSA-306).

CVE-2019-18423: A malicious guest administrator may cause a hypervisor crash, resulting in a Denial of Service (DoS). (bsc#1154460).

CVE-2019-18424: An untrusted domain with access to a physical device can DMA into host memory, leading to privilege escalation.
(bsc#1154461).

CVE-2019-18422: A malicious ARM guest might contrive to arrange for critical Xen code to run with interrupts erroneously enabled. This could lead to data corruption, denial of service, or possibly even privilege escalation. However a precise attack technique has not been identified. (bsc#1154464)

Note that Tenable Network Security has extracted the preceding description block directly from the SUSE security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

This update for xen fixes the following issues :

CVE-2019-19581: Fixed a potential out of bounds on 32-bit Arm (bsc#1158003 XSA-307).

CVE-2019-19582: Fixed a potential infinite loop when x86 accesses to bitmaps with a compile time known size of 64 (bsc#1158003 XSA-307).

CVE-2019-19583: Fixed improper checks which could have allowed HVM/PVH guest userspace code to crash the guest,leading to a guest denial of service (bsc#1158004 XSA-308).

CVE-2019-19578: Fixed an issue where a malicious or buggy PV guest could have caused hypervisor crash resulting in denial of service affecting the entire host (bsc#1158005 XSA-309).

CVE-2019-19580: Fixed a privilege escalation where a malicious PV guest administrator could have been able to escalate their privilege to that of the host (bsc#1158006 XSA-310).

CVE-2019-19577: Fixed an issue where a malicious guest administrator could have caused Xen to access data structures while they are being modified leading to a crash (bsc#1158007 XSA-311).

CVE-2019-19579: Fixed a privilege escaltion where an untrusted domain with access to a physical device can DMA into host memory (bsc#1157888 XSA-306).

CVE-2019-18423: A malicious guest administrator may cause a hypervisor crash, resulting in a Denial of Service (DoS) (bsc#1154460 XSA-301).

CVE-2019-18422: A malicious ARM guest might contrive to arrange for critical Xen code to run with interrupts erroneously enabled. This could lead to data corruption, denial of service, or possibly even privilege escalation. However a precise attack technique has not been identified. (bsc#1154464 XSA-303)

Note that Tenable Network Security has extracted the preceding description block directly from the SUSE security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

This update for xen fixes the following issues :

CVE-2019-19581: Fixed a potential out of bounds on 32-bit Arm (bsc#1158003 XSA-307).

CVE-2019-19582: Fixed a potential infinite loop when x86 accesses to bitmaps with a compile time known size of 64 (bsc#1158003 XSA-307).

CVE-2019-19583: Fixed improper checks which could have allowed HVM/PVH guest userspace code to crash the guest,leading to a guest denial of service (bsc#1158004 XSA-308).

CVE-2019-19578: Fixed an issue where a malicious or buggy PV guest could have caused hypervisor crash resulting in denial of service affecting the entire host (bsc#1158005 XSA-309).

CVE-2019-19580: Fixed a privilege escalation where a malicious PV guest administrator could have been able to escalate their privilege to that of the host (bsc#1158006 XSA-310).

CVE-2019-19577: Fixed an issue where a malicious guest administrator could have caused Xen to access data structures while they are being modified leading to a crash (bsc#1158007 XSA-311).

CVE-2019-19579: Fixed a privilege escaltion where an untrusted domain with access to a physical device can DMA into host memory (bsc#1157888 XSA-306).

CVE-2019-18420: Malicious x86 PV guests may have caused a hypervisor crash, resulting in a denial of service (bsc#1154448 XSA-296)

CVE-2019-18425: 32-bit PV guest user mode could elevate its privileges to that of the guest kernel. (bsc#1154456 XSA-298).

CVE-2019-18421: A malicious PV guest administrator may have been able to escalate their privilege to that of the host. (bsc#1154458 XSA-299).

CVE-2019-18423: A malicious guest administrator may cause a hypervisor crash, resulting in a denial of service (bsc#1154460 XSA-301).

CVE-2019-18422: A malicious ARM guest might contrive to arrange for critical Xen code to run with interrupts erroneously enabled. This could lead to data corruption, denial of service, or possibly even privilege escalation. However a precise attack technique has not been identified. (bsc#1154464 XSA-303)

CVE-2019-18424: An untrusted domain with access to a physical device can DMA into host memory, leading to privilege escalation.
(bsc#1154461 XSA-302).

CVE-2018-12207: Untrusted virtual machines on Intel CPUs could exploit a race condition in the Instruction Fetch Unit of the Intel CPU to cause a Machine Exception during Page Size Change, causing the CPU core to be non-functional. (bsc#1155945 XSA-304)

CVE-2019-11135: Aborting an asynchronous TSX operation on Intel CPUs with Transactional Memory support could be used to facilitate sidechannel information leaks out of microarchitectural buffers, similar to the previously described 'Microarchitectural Data Sampling' attack. (bsc#1152497 XSA-305).

Note that Tenable Network Security has extracted the preceding description block directly from the SUSE security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

add missing XSA-299 patches x86: Machine Check Error on Page Size Change DoS [XSA-304, CVE-2018-12207] TSX Asynchronous Abort speculative side channel [XSA-305, CVE-2019-11135]

----

VCPUOP_initialise DoS [XSA-296, CVE-2019-18420] missing descriptor table limit checking in x86 PV emulation [XSA-298, CVE-2019-18425] Issues with restartable PV type change operations [XSA-299, CVE-2019-18421] (#1767726) add-to-physmap can be abused to DoS Arm hosts [XSA-301, CVE-2019-18423] passed through PCI devices may corrupt host memory after deassignment [XSA-302, CVE-2019-18424] (#1767731) ARM: Interrupts are unconditionally unmasked in exception handlers [XSA-303, CVE-2019-18422]

Note that Tenable Network Security has extracted the preceding description block directly from the Fedora update system website.
Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

add missing XSA-299 patches

----

x86: Machine Check Error on Page Size Change DoS [XSA-304, CVE-2018-12207] TSX Asynchronous Abort speculative side channel [XSA-305, CVE-2019-11135]

----

VCPUOP_initialise DoS [XSA-296, CVE-2019-18420] missing descriptor table limit checking in x86 PV emulation [XSA-298, CVE-2019-18425] Issues with restartable PV type change operations [XSA-299, CVE-2019-18421] add-to-physmap can be abused to DoS Arm hosts [XSA-301, CVE-2019-18423] passed through PCI devices may corrupt host memory after deassignment [XSA-302, CVE-2019-18424] ARM: Interrupts are unconditionally unmasked in exception handlers [XSA-303, CVE-2019-18422]

Note that Tenable Network Security has extracted the preceding description block directly from the Fedora update system website.
Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

VCPUOP_initialise DoS [XSA-296, CVE-2019-18420] missing descriptor table limit checking in x86 PV emulation [XSA-298, CVE-2019-18425] Issues with restartable PV type change operations [XSA-299, CVE-2019-18421] (#1767726) add-to-physmap can be abused to DoS Arm hosts [XSA-301, CVE-2019-18423] passed through PCI devices may corrupt host memory after deassignment [XSA-302, CVE-2019-18424] (#1767731) ARM: Interrupts are unconditionally unmasked in exception handlers [XSA-303, CVE-2019-18422]

Note that Tenable Network Security has extracted the preceding description block directly from the Fedora update system website.
Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

This update for xen fixes the following issues :

  - CVE-2018-12207: Untrusted virtual machines on Intel CPUs     could exploit a race condition in the Instruction Fetch     Unit of the Intel CPU to cause a Machine Exception     during Page Size Change, causing the CPU core to be     non-functional. (bsc#1155945)

  - CVE-2019-11135: Aborting an asynchronous TSX operation     on Intel CPUs with Transactional Memory support could be     used to facilitate sidechannel information leaks out of     microarchitectural buffers, similar to the previously     described 'Microarchitectural Data Sampling' attack.
    (bsc#1152497).

  - CVE-2019-18423: A malicious guest administrator may     cause a hypervisor crash, resulting in a Denial of     Service (DoS). (bsc#1154460).

  - CVE-2019-18422: A malicious ARM guest might contrive to     arrange for critical Xen code to run with interrupts     erroneously enabled. This could lead to data corruption,     denial of service, or possibly even privilege     escalation. However a precise attack technique has not     been identified. (bsc#1154464)

  - CVE-2019-18424: An untrusted domain with access to a     physical device can DMA into host memory, leading to     privilege escalation. (bsc#1154461).

  - CVE-2019-18421: A malicious PV guest administrator may     have been able to escalate their privilege to that of     the host. (bsc#1154458).

  - CVE-2019-18425: 32-bit PV guest user mode could elevate     its privileges to that of the guest kernel.
    (bsc#1154456).

  - CVE-2019-18420: Malicious x86 PV guests may have caused     a hypervisor crash, resulting in a Denial of Service     (Dos). (bsc#1154448)

  - Upstream bug fixes (bsc#1027519)

This update was imported from the SUSE:SLE-15-SP1:Update update project.

This update for xen fixes the following issues :

CVE-2018-12207: Untrusted virtual machines on Intel CPUs could exploit a race condition in the Instruction Fetch Unit of the Intel CPU to cause a Machine Exception during Page Size Change, causing the CPU core to be non-functional. (bsc#1155945)

CVE-2019-11135: Aborting an asynchronous TSX operation on Intel CPUs with Transactional Memory support could be used to facilitate sidechannel information leaks out of microarchitectural buffers, similar to the previously described 'Microarchitectural Data Sampling' attack. (bsc#1152497).

CVE-2019-18423: A malicious guest administrator may cause a hypervisor crash, resulting in a Denial of Service (DoS). (bsc#1154460).

CVE-2019-18422: A malicious ARM guest might contrive to arrange for critical Xen code to run with interrupts erroneously enabled. This could lead to data corruption, denial of service, or possibly even privilege escalation. However a precise attack technique has not been identified. (bsc#1154464)

CVE-2019-18424: An untrusted domain with access to a physical device can DMA into host memory, leading to privilege escalation.
(bsc#1154461).

CVE-2019-18421: A malicious PV guest administrator may have been able to escalate their privilege to that of the host. (bsc#1154458).

CVE-2019-18425: 32-bit PV guest user mode could elevate its privileges to that of the guest kernel. (bsc#1154456).

CVE-2019-18420: Malicious x86 PV guests may have caused a hypervisor crash, resulting in a Denial of Service (Dos). (bsc#1154448)

Upstream bug fixes (bsc#1027519)

Note that Tenable Network Security has extracted the preceding description block directly from the SUSE security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

ID	Name	Product	Family	Severity
255894	Linux Distros Unpatched Vulnerability : CVE-2019-18422	Nessus	Misc.	high
424706	Alpine: multiple xen packages: security update to 4.13.0-r0	Tenable Cloud Security	Alpine Linux Local Security Checks	critical
424706	Alpine: multiple xen packages: security update to 4.13.0-r0	Tenable Self-Hosted Container Security	Alpine Linux Local Security Checks	critical
407758	Alpine: xen: security update to 4.12.1-r1	Tenable Cloud Security	Alpine Linux Local Security Checks	critical
407758	Alpine: xen: security update to 4.12.1-r1	Tenable Self-Hosted Container Security	Alpine Linux Local Security Checks	critical
407749	Alpine: xen: security update to 4.11.2-r1	Tenable Cloud Security	Alpine Linux Local Security Checks	critical
407749	Alpine: xen: security update to 4.11.2-r1	Tenable Self-Hosted Container Security	Alpine Linux Local Security Checks	critical
407741	Alpine: xen: security update to 4.10.4-r1	Tenable Cloud Security	Alpine Linux Local Security Checks	critical
407741	Alpine: xen: security update to 4.10.4-r1	Tenable Self-Hosted Container Security	Alpine Linux Local Security Checks	critical
132875	Debian DSA-4602-1 : xen - security update (MDSUM/RIDL) (MFBDS/RIDL/ZombieLoad) (MLPDS/RIDL) (MSBDS/Fallout)	Nessus	Debian Local Security Checks	critical
132092	SUSE SLED12 / SLES12 Security Update : xen (SUSE-SU-2019:3310-1)	Nessus	SuSE Local Security Checks	high
132091	SUSE SLED15 / SLES15 Security Update : xen (SUSE-SU-2019:3309-1)	Nessus	SuSE Local Security Checks	high
132073	SUSE SLES12 Security Update : xen (SUSE-SU-2019:3297-1)	Nessus	SuSE Local Security Checks	critical
131460	Fedora 30 : xen (2019-cbb732f760)	Nessus	Fedora Local Security Checks	critical
131143	Fedora 31 : xen (2019-376ec5c107)	Nessus	Fedora Local Security Checks	critical
131098	Fedora 29 : xen (2019-865bb16900)	Nessus	Fedora Local Security Checks	critical
131062	openSUSE Security Update : xen (openSUSE-2019-2508)	Nessus	SuSE Local Security Checks	critical
130959	SUSE SLED15 / SLES15 Security Update : xen (SUSE-SU-2019:2961-1)	Nessus	SuSE Local Security Checks	critical

Detections

Analytics

CVE-2019-18422

high

Tenable Plugins

high

critical

critical

critical

critical

critical

critical

critical

critical

critical

high

high

critical

critical

critical

critical

critical

critical