x86 shadow paging arbitrary pointer dereference In environments where host assisted address translation is necessary but Hardware Assisted Paging (HAP) is unavailable, Xen will run guests in so called shadow mode. Due to too lax a check in one of the hypervisor routines used for shadow page handling it is possible for a guest with a PCI device passed through to cause the hypervisor to access an arbitrary pointer partially under guest control.

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

  - x86 shadow paging arbitrary pointer dereference In environments where host assisted address translation is     necessary but Hardware Assisted Paging (HAP) is unavailable, Xen will run guests in so called shadow mode.
    Due to too lax a check in one of the hypervisor routines used for shadow page handling it is possible for     a guest with a PCI device passed through to cause the hypervisor to access an arbitrary pointer partially     under guest control. (CVE-2022-42335)

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:

  - x86: speculative vulnerability in 32bit SYSCALL path Due to an oversight in the very original
    Spectre/Meltdown security work (XSA-254), one entrypath performs its speculation-safety actions too late.
    In some configurations, there is an unprotected RET instruction which can be attacked with a variety of
    speculative attacks. (CVE-2022-42331)

  - x86 shadow plus log-dirty mode use-after-free In environments where host assisted address translation is
    necessary but Hardware Assisted Paging (HAP) is unavailable, Xen will run guests in so called shadow mode.
    Shadow mode maintains a pool of memory used for both shadow page tables as well as auxiliary data
    structures. To migrate or snapshot guests, Xen additionally runs them in so called log-dirty mode. The
    data structures needed by the log-dirty tracking are part of aformentioned auxiliary data. In order to
    keep error handling efforts within reasonable bounds, for operations which may require memory allocations
    shadow mode logic ensures up front that enough memory is available for the worst case requirements.
    Unfortunately, while page table memory is properly accounted for on the code path requiring the potential
    establishing of new shadows, demands by the log-dirty infrastructure were not taken into consideration. As
    a result, just established shadow page tables could be freed again immediately, while other code is still
    accessing them on the assumption that they would remain allocated. (CVE-2022-42332)

  - x86/HVM pinned cache attributes mis-handling T[his CNA information record relates to multiple CVEs; the
    text explains which aspects/vulnerabilities correspond to which CVE.] To allow cachability control for HVM
    guests with passed through devices, an interface exists to explicitly override defaults which would
    otherwise be put in place. While not exposed to the affected guests themselves, the interface specifically
    exists for domains controlling such guests. This interface may therefore be used by not fully privileged
    entities, e.g. qemu running deprivileged in Dom0 or qemu running in a so called stub-domain. With this
    exposure it is an issue that - the number of the such controlled regions was unbounded (CVE-2022-42333), -
    installation and removal of such regions was not properly serialized (CVE-2022-42334). (CVE-2022-42333)

  - x86 shadow paging arbitrary pointer dereference In environments where host assisted address translation is
    necessary but Hardware Assisted Paging (HAP) is unavailable, Xen will run guests in so called shadow mode.
    Due to too lax a check in one of the hypervisor routines used for shadow page handling it is possible for
    a guest with a PCI device passed through to cause the hypervisor to access an arbitrary pointer partially
    under guest control. (CVE-2022-42335)

The remote host is affected by the vulnerability described in GLSA-202402-07 (Xen: Multiple Vulnerabilities)

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

Tenable has extracted the preceding description block directly from the Gentoo Linux security advisory.

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

The remote SUSE Linux SLED15 / SLED_SAP15 / SLES15 / SLES_SAP15 / openSUSE 15 host has packages installed that are affected by multiple vulnerabilities as referenced in the SUSE-SU-2023:2535-1 advisory.

    Security fixes:

    - CVE-2022-42336: Fix an issue where guests configuring AMD       Speculative Store Bypass Disable would have no effect (XSA-431)       (bsc#1211433).
    - CVE-2022-42335: Fixed an issue where guests running under shadow       mode with a PCI devices passed through could force the hypervisor       to dereference arbitrary memory, leading to a denial of service       (XSA-430) (bsc#1210315).

    Non-security fixes:

    - Fixed a build warning false positive (bsc#1210570).
    - Added missing debug-info to xen-syms (bsc#1209237).
    - Updated to version 4.17.1 (bsc#1027519).
    - Fixed a failure during VM destruction when using host-assisted kexec       and kdump (bsc#1209245).
    - Other upstream fixes (bsc#1027519).

Tenable has extracted the preceding description block directly from the SUSE security advisory.

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

The remote Fedora 38 host has a package installed that is affected by a vulnerability as referenced in the FEDORA-2023-d28433ead1 advisory.

    x86 shadow paging arbitrary pointer dereference [XSA-430, CVE-2022-42335]

Tenable has extracted the preceding description block directly from the Fedora security advisory.

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

ID	Name	Product	Family	Severity
251078	Linux Distros Unpatched Vulnerability : CVE-2022-42335	Nessus	Misc.	high
424717	Alpine: multiple xen packages: security update to 4.17.0-r5	Tenable Cloud Security	Alpine Linux Local Security Checks	high
424717	Alpine: multiple xen packages: security update to 4.17.0-r5	Tenable Self-Hosted Container Security	Alpine Linux Local Security Checks	high
189976	GLSA-202402-07 : Xen: Multiple Vulnerabilities	Nessus	Gentoo Local Security Checks	high
177438	SUSE SLED15: xen / xen-devel / xen-doc-html / xen-libs / xen-libs-32bit / etc (SUSE-SU-2023:2535-1)	Nessus	SuSE Local Security Checks	high
174914	Fedora 38 : xen (2023-d28433ead1)	Nessus	Fedora Local Security Checks	high

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