An issue was discovered in Xen through 4.12.x allowing ARM guest OS users to cause a denial of service via a XENMEM_add_to_physmap hypercall. p2m->max_mapped_gfn is used by the functions p2m_resolve_translation_fault() and p2m_get_entry() to sanity check guest physical frame. The rest of the code in the two functions will assume that there is a valid root table and check that with BUG_ON(). The function p2m_get_root_pointer() will ignore the unused top bits of a guest physical frame. This means that the function p2m_set_entry() will alias the frame. However, p2m->max_mapped_gfn will be updated using the original frame. It would be possible to set p2m->max_mapped_gfn high enough to cover a frame that would lead p2m_get_root_pointer() to return NULL in p2m_get_entry() and p2m_resolve_translation_fault(). Additionally, the sanity check on p2m->max_mapped_gfn is off-by-one allowing "highest mapped + 1" to be considered valid. However, p2m_get_root_pointer() will return NULL. The problem could be triggered with a specially crafted hypercall XENMEM_add_to_physmap{, _batch} followed by an access to an address (via hypercall or direct access) that passes the sanity check but cause p2m_get_root_pointer() to return NULL. A malicious guest administrator may cause a hypervisor crash, resulting in a Denial of Service (DoS). Xen version 4.8 and newer are vulnerable. Only Arm systems are vulnerable. x86 systems are not affected.

The remote host is affected by the vulnerability described in GLSA-202003-56 (Xen: Multiple vulnerabilities)

    Multiple vulnerabilities have been discovered in Xen. Please review the       referenced CVE identifiers for details.
  Impact :

    A local attacker could potentially gain privileges on the host system or       cause a Denial of Service condition.
  Workaround :

    There is no known workaround at this time.

According to its self-reported version number, the Xen Hypervisor installed on the remote host is affected by a denial of service vulnerability due to improper validation of input data. An authenticated, remote attack can exploit this, via a specially crafted hypercall followed by an access to an address that passes the sanity check but causes a hypervisor crash . 

Note that Nessus has checked the changeset versions based on the xen.git change log. Nessus did not check guest hardware configurations or if patches were applied manually to the source code before a recompile and reinstall.

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
134964	GLSA-202003-56 : Xen: Multiple vulnerabilities (MDSUM/RIDL) (MFBDS/RIDL/ZombieLoad) (MLPDS/RIDL) (MSBDS/Fallout)	Nessus	Gentoo Local Security Checks	critical
132934	Xen Denial of Service Vulnerability (XSA-301)	Nessus	Misc.	high
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-2019-18423

high

Tenable Plugins

critical

high

critical

high

high

critical

critical

critical

critical

critical

critical