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.

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 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)

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

The remote SUSE Linux SLES11 host has packages installed that are affected by multiple vulnerabilities as referenced in the SUSE-SU-2020:14444-1 advisory.

  - 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 cause a denial of service     via a VCPUOP_initialise hypercall. hypercall_create_continuation() is a variadic function which uses a     printf-like format string to interpret its parameters. Error handling for a bad format character was done     using BUG(), which crashes Xen. One path, via the VCPUOP_initialise hypercall, has a bad format character.
    The BUG() can be hit if VCPUOP_initialise executes for a sufficiently long period of time for a     continuation to be created. Malicious guests may cause a hypervisor crash, resulting in a Denial of     Service (DoS). Xen versions 4.6 and newer are vulnerable. Xen versions 4.5 and earlier are not vulnerable.
    Only x86 PV guests can exploit the vulnerability. HVM and PVH guests, and guests on ARM systems, cannot     exploit the vulnerability. (CVE-2019-18420)

  - 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 attackers to gain host OS privileges via DMA in a     situation where an untrusted domain has access to a physical device. This occurs because passed through     PCI devices may corrupt host memory after deassignment. When a PCI device is assigned to an untrusted     domain, it is possible for that domain to program the device to DMA to an arbitrary address. The IOMMU is     used to protect the host from malicious DMA by making sure that the device addresses can only target     memory assigned to the guest. However, when the guest domain is torn down, or the device is deassigned,     the device is assigned back to dom0, thus allowing any in-flight DMA to potentially target critical host     data. An untrusted domain with access to a physical device can DMA into host memory, leading to privilege     escalation. Only systems where guests are given direct access to physical devices capable of DMA (PCI     pass-through) are vulnerable. Systems which do not use PCI pass-through are not vulnerable.
    (CVE-2019-18424)

  - 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)

  - An issue was discovered in Xen through 4.12.x allowing x86 AMD HVM guest OS users to cause a denial of     service or possibly gain privileges by triggering data-structure access during pagetable-height updates.
    When running on AMD systems with an IOMMU, Xen attempted to dynamically adapt the number of levels of     pagetables (the pagetable height) in the IOMMU according to the guest's address space size. The code to     select and update the height had several bugs. Notably, the update was done without taking a lock which is     necessary for safe operation. A malicious guest administrator can cause Xen to access data structures     while they are being modified, causing Xen to crash. Privilege escalation is thought to be very difficult     but cannot be ruled out. Additionally, there is a potential memory leak of 4kb per guest boot, under     memory pressure. Only Xen on AMD CPUs is vulnerable. Xen running on Intel CPUs is not vulnerable. ARM     systems are not vulnerable. Only systems where guests are given direct access to physical devices are     vulnerable. Systems which do not use PCI pass-through are not vulnerable. Only HVM guests can exploit the     vulnerability. PV and PVH guests cannot. All versions of Xen with IOMMU support are vulnerable.
    (CVE-2019-19577)

  - An issue was discovered in Xen through 4.12.x allowing x86 PV guest OS users to cause a denial of service     via degenerate chains of linear pagetables, because of an incorrect fix for CVE-2017-15595. Linear     pagetables is a technique which involves either pointing a pagetable at itself, or to another pagetable     of the same or higher level. Xen has limited support for linear pagetables: A page may either point to     itself, or point to another pagetable of the same level (i.e., L2 to L2, L3 to L3, and so on). XSA-240     introduced an additional restriction that limited the depth of such chains by allowing pages to either
    *point to* other pages of the same level, or *be pointed to* by other pages of the same level, but not     both. To implement this, we keep track of the number of outstanding times a page points to or is pointed     to another page table, to prevent both from happening at the same time. Unfortunately, the original commit     introducing this reset this count when resuming validation of a partially-validated pagetable, incorrectly     dropping some linear_pt_entry counts. If an attacker could engineer such a situation to occur, they     might be able to make loops or other arbitrary chains of linear pagetables, as described in XSA-240. A     malicious or buggy PV guest may cause the hypervisor to crash, resulting in Denial of Service (DoS)     affecting the entire host. Privilege escalation and information leaks cannot be excluded. All versions of     Xen are vulnerable. Only x86 systems are affected. Arm systems are not affected. Only x86 PV guests can     leverage the vulnerability. x86 HVM and PVH guests cannot leverage the vulnerability. Only systems which     have enabled linear pagetables are vulnerable. Systems which have disabled linear pagetables, either by     selecting CONFIG_PV_LINEAR_PT=n when building the hypervisor, or adding pv-linear-pt=false on the command-     line, are not vulnerable. (CVE-2019-19578)

  - An issue was discovered in Xen through 4.12.x allowing attackers to gain host OS privileges via DMA in a     situation where an untrusted domain has access to a physical device (and assignable-add is not used),     because of an incomplete fix for CVE-2019-18424. XSA-302 relies on the use of libxl's assignable-add     feature to prepare devices to be assigned to untrusted guests. Unfortunately, this is not considered a     strictly required step for device assignment. The PCI passthrough documentation on the wiki describes     alternate ways of preparing devices for assignment, and libvirt uses its own ways as well. Hosts where     these alternate methods are used will still leave the system in a vulnerable state after the device     comes back from a guest. An untrusted domain with access to a physical device can DMA into host memory,     leading to privilege escalation. Only systems where guests are given direct access to physical devices     capable of DMA (PCI pass-through) are vulnerable. Systems which do not use PCI pass-through are not     vulnerable. (CVE-2019-19579)

  - 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, because of an incomplete fix     for CVE-2019-18421. XSA-299 addressed several critical issues in restartable PV type change operations.
    Despite extensive testing and auditing, some corner cases were missed. A malicious PV guest administrator     may be able to escalate their privilege to that of the host. All security-supported versions of Xen are     vulnerable. Only x86 systems are affected. Arm systems are not affected. Only x86 PV guests can leverage     the vulnerability. x86 HVM and PVH guests cannot leverage the vulnerability. Note that these attacks     require very precise timing, which may be difficult to exploit in practice. (CVE-2019-19580)

  - An issue was discovered in Xen through 4.12.x allowing x86 HVM/PVH guest OS users to cause a denial of     service (guest OS crash) because VMX VMEntry checks mishandle a certain case. Please see XSA-260 for     background on the MovSS shadow. Please see XSA-156 for background on the need for #DB interception. The     VMX VMEntry checks do not like the exact combination of state which occurs when #DB in intercepted, Single     Stepping is active, and blocked by STI/MovSS is active, despite this being a legitimate state to be in.
    The resulting VMEntry failure is fatal to the guest. HVM/PVH guest userspace code may be able to crash the     guest, resulting in a guest Denial of Service. All versions of Xen are affected. Only systems supporting     VMX hardware virtual extensions (Intel, Cyrix, or Zhaoxin CPUs) are affected. Arm and AMD systems are     unaffected. Only HVM/PVH guests are affected. PV guests cannot leverage the vulnerability.
    (CVE-2019-19583)

  - An issue was discovered in xenoprof in Xen through 4.13.x, allowing guest OS users (without active     profiling) to obtain sensitive information about other guests. Unprivileged guests can request to map     xenoprof buffers, even if profiling has not been enabled for those guests. These buffers were not     scrubbed. (CVE-2020-11740)

  - An issue was discovered in xenoprof in Xen through 4.13.x, allowing guest OS users (with active profiling)     to obtain sensitive information about other guests, cause a denial of service, or possibly gain     privileges. For guests for which active profiling was enabled by the administrator, the xenoprof code     uses the standard Xen shared ring structure. Unfortunately, this code did not treat the guest as a     potential adversary: it trusts the guest not to modify buffer size information or modify head / tail     pointers in unexpected ways. This can crash the host (DoS). Privilege escalation cannot be ruled out.
    (CVE-2020-11741)

  - An issue was discovered in Xen through 4.13.x, allowing guest OS users to cause a denial of service     because of bad continuation handling in GNTTABOP_copy. Grant table operations are expected to return 0 for     success, and a negative number for errors. The fix for CVE-2017-12135 introduced a path through grant copy     handling where success may be returned to the caller without any action taken. In particular, the status     fields of individual operations are left uninitialised, and may result in errant behaviour in the caller     of GNTTABOP_copy. A buggy or malicious guest can construct its grant table in such a way that, when a     backend domain tries to copy a grant, it hits the incorrect exit path. This returns success to the caller     without doing anything, which may cause crashes or other incorrect behaviour. (CVE-2020-11742)

  - tftp.c in libslirp 4.1.0, as used in QEMU 4.2.0, does not prevent ..\ directory traversal on Windows.
    (CVE-2020-7211)

  - In libslirp 4.1.0, as used in QEMU 4.2.0, tcp_subr.c misuses snprintf return values, leading to a buffer     overflow in later code. (CVE-2020-8608)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

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.

This update for xen fixes the following issues :

CVE-2018-12207: Fixed a race condition where untrusted virtual machines could have been using 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-2018-19965: Fixed a DoS from attempting to use INVPCID with a non-canonical addresses (bsc#1115045 XSA-279).

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

CVE-2019-12067: Fixed a NULL pointer dereference in QEMU AHCI (bsc#1145652).

CVE-2019-12068: Fixed an infinite loop while executing script (bsc#1146874).

CVE-2019-12155: Fixed a NULL pointer dereference while releasing spice resources (bsc#1135905).

CVE-2019-14378: Fixed a heap buffer overflow during packet reassembly in slirp networking implementation (bsc#1143797).

CVE-2019-15890: Fixed a use-after-free during packet reassembly (bsc#1149813).

CVE-2019-17340: Fixed grant table transfer issues on large hosts (XSA-284 bsc#1126140).

CVE-2019-17341: Fixed a race with pass-through device hotplug (XSA-285 bsc#1126141).

CVE-2019-17342: Fixed steal_page violating page_struct access discipline (XSA-287 bsc#1126192).

CVE-2019-17343: Fixed an inconsistent PV IOMMU discipline (XSA-288 bsc#1126195).

CVE-2019-17344: Fixed a missing preemption in x86 PV page table unvalidation (XSA-290 bsc#1126196).

CVE-2019-17347: Fixed a PV kernel context switch corruption (XSA-293 bsc#1126201).

CVE-2019-18420: Fixed a hypervisor crash that could be caused by malicious x86 PV guests, resulting in a denial of service (bsc#1154448 XSA-296).

CVE-2019-18421: Fixed a privilege escalation through malicious PV guest administrators (bsc#1154458 XSA-299).

CVE-2019-18424: Fixed a privilege escalation through DMA to physical devices by untrusted domains (bsc#1154461 XSA-302).

CVE-2019-18425: Fixed a privilege escalation from 32-bit PV guest used mode (bsc#1154456 XSA-298).

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-2019-19578: 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-2019-19579: Fixed a privilege escalation where an untrusted domain with access to a physical device can DMA into host memory (bsc#1157888 XSA-306).

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-2019-19581: Fixed a potential out of bounds on 32-bit Arm (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).

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-2020-7211: potential directory traversal using relative paths via tftp server on Windows host (bsc#1161181).

CVE-2019-19579: Device quarantine for alternate pci assignment methods (bsc#1157888).

CVE-2019-19581: find_next_bit() issues (bsc#1158003).

CVE-2019-19583: VMentry failure with debug exceptions and blocked states (bsc#1158004).

CVE-2019-19578: Linear pagetable use / entry miscounts (bsc#1158005).

CVE-2019-19580: Further issues with restartable PV type change operations (bsc#1158006).

CVE-2019-19577: dynamic height for the IOMMU pagetables (bsc#1158007).

CVE-2019-18420: VCPUOP_initialise DoS (bsc#1154448).

CVE-2019-18425: missing descriptor table limit checking in x86 PV emulation (bsc#1154456).

CVE-2019-18421: Issues with restartable PV type change operations (bsc#1154458).

CVE-2019-18424: passed through PCI devices may corrupt host memory after deassignment (bsc#1154461).

CVE-2018-12207: Machine Check Error Avoidance on Page Size Change (aka IFU issue) (bsc#1155945).

CVE-2019-11135: TSX Asynchronous Abort (TAA) issue (bsc#1152497).

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.

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-2019-18420: 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-2019-18425: 32-bit PV guest user mode could elevate     its privileges to that of the guest kernel.
    (bsc#1154456).

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

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

This update was imported from the SUSE:SLE-15: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-2019-18424: 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)

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-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.

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

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

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

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.

According to its self-reported version number, the Xen hypervisor installed on the remote host is affected by a privilege escalation vulnerability due to improper bounds checking for descriptor table accesses. An authenticated attacker, in user mode on a 32-bit guest, could leverage this vulnerability to elevate privileges to that of the guest kernel. Only 32-bit PV guest user mode can leverage this vulnerability.

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.

ID	Name	Product	Family	Severity
250427	Linux Distros Unpatched Vulnerability : CVE-2019-18425	Nessus	Misc.	critical
150584	SUSE SLES11 Security Update : xen (SUSE-SU-2020:14444-1)	Nessus	SuSE Local Security Checks	critical
134964	GLSA-202003-56 : Xen: Multiple vulnerabilities (MDSUM/RIDL) (MFBDS/RIDL/ZombieLoad) (MLPDS/RIDL) (MSBDS/Fallout)	Nessus	Gentoo Local Security Checks	critical
133763	SUSE SLES12 Security Update : xen (SUSE-SU-2020:0388-1)	Nessus	SuSE Local Security Checks	critical
133539	SUSE SLES12 Security Update : xen (SUSE-SU-2020:0334-1)	Nessus	SuSE 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
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
131060	openSUSE Security Update : xen (openSUSE-2019-2506)	Nessus	SuSE Local Security Checks	critical
130960	SUSE SLED12 / SLES12 Security Update : xen (SUSE-SU-2019:2962-1)	Nessus	SuSE Local Security Checks	critical
130959	SUSE SLED15 / SLES15 Security Update : xen (SUSE-SU-2019:2961-1)	Nessus	SuSE Local Security Checks	critical
130958	SUSE SLED15 / SLES15 Security Update : xen (SUSE-SU-2019:2960-1)	Nessus	SuSE Local Security Checks	critical
130760	Xen Project Descriptor Table Limit Checking Privilege Escalation Vulnerability (XSA-298)	Nessus	Misc.	critical

Detections

Analytics

CVE-2019-18425

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