[This CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.] AMD CPUs since ~2014 have extensions to normal x86 debugging functionality. Xen supports guests using these extensions. Unfortunately there are errors in Xen's handling of the guest state, leading to denials of service. 1) CVE-2023-34327 - An HVM vCPU can end up operating in the context of a previous vCPUs debug mask state. 2) CVE-2023-34328 - A PV vCPU can place a breakpoint over the live GDT. This allows the PV vCPU to exploit XSA-156 / CVE-2015-8104 and lock up the CPU entirely.

The remote openSUSE 15 host has packages installed that are affected by multiple vulnerabilities as referenced in the SUSE-SU-2023:4476-1 advisory.

  - A division-by-zero error on some AMD processors can potentially return speculative data resulting in loss     of confidentiality. (CVE-2023-20588)

  - arm32: The cache may not be properly cleaned/invalidated [XSA-437, CVE-2023-34321] top-level shadow     reference dropped too early for 64-bit PV guests [XSA-438, CVE-2023-34322] x86/AMD: Divide speculative     information leak [XSA-439, CVE-2023-20588] (CVE-2023-34322)

  - The vulnerability exists due to insufficient validation of user-supplied input in libfsimage. A remote     guest can use pygrab to trigger stack-based buffer overflow and execute arbitrary code on the host system     (CVE-2023-34325)

  - The vulnerability exists due to missing IOMMU TLB flushing on x86/AMD systems. A malicious guest can     access memory not owned by the guest and escalate privileges on the system. (CVE-2023-34326)

  - The vulnerability exists due to improper validation of guest state when using Debug Masks in HVM vCPU. A     malicious guest can perform a denial of service (DoS) attack against the guest OS. (CVE-2023-34327)

  - The vulnerability exists due to improper validation of guest state in PV vCPU. A malicious guest place a     breakpoint over the live GDT and perform a denial of service (DoS) attack against the host.
    (CVE-2023-34328)

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

The remote openSUSE 15 host has packages installed that are affected by multiple vulnerabilities as referenced in the SUSE-SU-2023:4475-1 advisory.

  - A division-by-zero error on some AMD processors can potentially return speculative data resulting in loss     of confidentiality. (CVE-2023-20588)

  - arm32: The cache may not be properly cleaned/invalidated [XSA-437, CVE-2023-34321] top-level shadow     reference dropped too early for 64-bit PV guests [XSA-438, CVE-2023-34322] x86/AMD: Divide speculative     information leak [XSA-439, CVE-2023-20588] (CVE-2023-34322)

  - The vulnerability exists due to insufficient validation of user-supplied input in libfsimage. A remote     guest can use pygrab to trigger stack-based buffer overflow and execute arbitrary code on the host system     (CVE-2023-34325)

  - The vulnerability exists due to missing IOMMU TLB flushing on x86/AMD systems. A malicious guest can     access memory not owned by the guest and escalate privileges on the system. (CVE-2023-34326)

  - The vulnerability exists due to improper validation of guest state when using Debug Masks in HVM vCPU. A     malicious guest can perform a denial of service (DoS) attack against the guest OS. (CVE-2023-34327)

  - The vulnerability exists due to improper validation of guest state in PV vCPU. A malicious guest place a     breakpoint over the live GDT and perform a denial of service (DoS) attack against the host.
    (CVE-2023-34328)

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 39 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2023-de338d9f37 advisory.

  - When a transaction is committed, C Xenstored will first check the quota is correct before attempting to     commit any nodes. It would be possible that accounting is temporarily negative if a node has been removed     outside of the transaction. Unfortunately, some versions of C Xenstored are assuming that the quota cannot     be negative and are using assert() to confirm it. This will lead to C Xenstored crash when tools are built     without -DNDEBUG (this is the default). (CVE-2023-34323)

  - [This CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities     correspond to which CVE.] libfsimage contains parsing code for several filesystems, most of them based on     grub-legacy code. libfsimage is used by pygrub to inspect guest disks. Pygrub runs as the same user as the     toolstack (root in a priviledged domain). At least one issue has been reported to the Xen Security Team     that allows an attacker to trigger a stack buffer overflow in libfsimage. After further analisys the Xen     Security Team is no longer confident in the suitability of libfsimage when run against guest controlled     input with super user priviledges. In order to not affect current deployments that rely on pygrub patches     are provided in the resolution section of the advisory that allow running pygrub in deprivileged mode.
    CVE-2023-4949 refers to the original issue in the upstream grub project (An attacker with local access to     a system (either through a disk or external drive) can present a modified XFS partition to grub-legacy in     such a way to exploit a memory corruption in grub's XFS file system implementation.) CVE-2023-34325     refers specifically to the vulnerabilities in Xen's copy of libfsimage, which is decended from a very old     version of grub. (CVE-2023-34325)

  - The caching invalidation guidelines from the AMD-Vi specification (48882Rev 3.07-PUBOct 2022) is     incorrect on some hardware, as devices will malfunction (see stale DMA mappings) if some fields of the DTE     are updated but the IOMMU TLB is not flushed. Such stale DMA mappings can point to memory ranges not owned     by the guest, thus allowing access to unindented memory regions. (CVE-2023-34326)

  - [This CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities     correspond to which CVE.] AMD CPUs since ~2014 have extensions to normal x86 debugging functionality. Xen     supports guests using these extensions. Unfortunately there are errors in Xen's handling of the guest     state, leading to denials of service. 1) CVE-2023-34327 - An HVM vCPU can end up operating in the context     of a previous vCPUs debug mask state. 2) CVE-2023-34328 - A PV vCPU can place a breakpoint over the live     GDT. This allows the PV vCPU to exploit XSA-156 / CVE-2015-8104 and lock up the CPU entirely.
    (CVE-2023-34327, CVE-2023-34328)

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 37 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2023-881672fdab advisory.

  - When a transaction is committed, C Xenstored will first check the quota is correct before attempting to     commit any nodes. It would be possible that accounting is temporarily negative if a node has been removed     outside of the transaction. Unfortunately, some versions of C Xenstored are assuming that the quota cannot     be negative and are using assert() to confirm it. This will lead to C Xenstored crash when tools are built     without -DNDEBUG (this is the default). (CVE-2023-34323)

  - [This CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities     correspond to which CVE.] libfsimage contains parsing code for several filesystems, most of them based on     grub-legacy code. libfsimage is used by pygrub to inspect guest disks. Pygrub runs as the same user as the     toolstack (root in a priviledged domain). At least one issue has been reported to the Xen Security Team     that allows an attacker to trigger a stack buffer overflow in libfsimage. After further analisys the Xen     Security Team is no longer confident in the suitability of libfsimage when run against guest controlled     input with super user priviledges. In order to not affect current deployments that rely on pygrub patches     are provided in the resolution section of the advisory that allow running pygrub in deprivileged mode.
    CVE-2023-4949 refers to the original issue in the upstream grub project (An attacker with local access to     a system (either through a disk or external drive) can present a modified XFS partition to grub-legacy in     such a way to exploit a memory corruption in grub's XFS file system implementation.) CVE-2023-34325     refers specifically to the vulnerabilities in Xen's copy of libfsimage, which is decended from a very old     version of grub. (CVE-2023-34325)

  - The caching invalidation guidelines from the AMD-Vi specification (48882Rev 3.07-PUBOct 2022) is     incorrect on some hardware, as devices will malfunction (see stale DMA mappings) if some fields of the DTE     are updated but the IOMMU TLB is not flushed. Such stale DMA mappings can point to memory ranges not owned     by the guest, thus allowing access to unindented memory regions. (CVE-2023-34326)

  - [This CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities     correspond to which CVE.] AMD CPUs since ~2014 have extensions to normal x86 debugging functionality. Xen     supports guests using these extensions. Unfortunately there are errors in Xen's handling of the guest     state, leading to denials of service. 1) CVE-2023-34327 - An HVM vCPU can end up operating in the context     of a previous vCPUs debug mask state. 2) CVE-2023-34328 - A PV vCPU can place a breakpoint over the live     GDT. This allows the PV vCPU to exploit XSA-156 / CVE-2015-8104 and lock up the CPU entirely.
    (CVE-2023-34327, CVE-2023-34328)

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 multiple vulnerabilities as referenced in the FEDORA-2023-a4c606585e advisory.

  - When a transaction is committed, C Xenstored will first check the quota is correct before attempting to     commit any nodes. It would be possible that accounting is temporarily negative if a node has been removed     outside of the transaction. Unfortunately, some versions of C Xenstored are assuming that the quota cannot     be negative and are using assert() to confirm it. This will lead to C Xenstored crash when tools are built     without -DNDEBUG (this is the default). (CVE-2023-34323)

  - [This CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities     correspond to which CVE.] libfsimage contains parsing code for several filesystems, most of them based on     grub-legacy code. libfsimage is used by pygrub to inspect guest disks. Pygrub runs as the same user as the     toolstack (root in a priviledged domain). At least one issue has been reported to the Xen Security Team     that allows an attacker to trigger a stack buffer overflow in libfsimage. After further analisys the Xen     Security Team is no longer confident in the suitability of libfsimage when run against guest controlled     input with super user priviledges. In order to not affect current deployments that rely on pygrub patches     are provided in the resolution section of the advisory that allow running pygrub in deprivileged mode.
    CVE-2023-4949 refers to the original issue in the upstream grub project (An attacker with local access to     a system (either through a disk or external drive) can present a modified XFS partition to grub-legacy in     such a way to exploit a memory corruption in grub's XFS file system implementation.) CVE-2023-34325     refers specifically to the vulnerabilities in Xen's copy of libfsimage, which is decended from a very old     version of grub. (CVE-2023-34325)

  - The caching invalidation guidelines from the AMD-Vi specification (48882Rev 3.07-PUBOct 2022) is     incorrect on some hardware, as devices will malfunction (see stale DMA mappings) if some fields of the DTE     are updated but the IOMMU TLB is not flushed. Such stale DMA mappings can point to memory ranges not owned     by the guest, thus allowing access to unindented memory regions. (CVE-2023-34326)

  - [This CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities     correspond to which CVE.] AMD CPUs since ~2014 have extensions to normal x86 debugging functionality. Xen     supports guests using these extensions. Unfortunately there are errors in Xen's handling of the guest     state, leading to denials of service. 1) CVE-2023-34327 - An HVM vCPU can end up operating in the context     of a previous vCPUs debug mask state. 2) CVE-2023-34328 - A PV vCPU can place a breakpoint over the live     GDT. This allows the PV vCPU to exploit XSA-156 / CVE-2015-8104 and lock up the CPU entirely.
    (CVE-2023-34327, CVE-2023-34328)

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 SLES15 / SLES_SAP15 host has packages installed that are affected by multiple vulnerabilities as referenced in the SUSE-SU-2023:4184-1 advisory.

  - The vulnerability exists due to a reachable assertion when handling negative quota values in C Xenstored.
    A malicious guest can craft a transaction that forces C Xenstored to check quota value and perform a     denial of service attack. (CVE-2023-34323)

  - The vulnerability exists due to insufficient validation of user-supplied input in libfsimage. A remote     guest can use pygrab to trigger stack-based buffer overflow and execute arbitrary code on the host system     (CVE-2023-34325)

  - The vulnerability exists due to missing IOMMU TLB flushing on x86/AMD systems. A malicious guest can     access memory not owned by the guest and escalate privileges on the system. (CVE-2023-34326)

  - The vulnerability exists due to improper validation of guest state when using Debug Masks in HVM vCPU. A     malicious guest can perform a denial of service (DoS) attack against the guest OS. (CVE-2023-34327)

  - The vulnerability exists due to improper validation of guest state in PV vCPU. A malicious guest place a     breakpoint over the live GDT and perform a denial of service (DoS) attack against the host.
    (CVE-2023-34328)

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 SLES15 / SLES_SAP15 host has packages installed that are affected by multiple vulnerabilities as referenced in the SUSE-SU-2023:4174-1 advisory.

  - The vulnerability exists due to a reachable assertion when handling negative quota values in C Xenstored.
    A malicious guest can craft a transaction that forces C Xenstored to check quota value and perform a     denial of service attack. (CVE-2023-34323)

  - The vulnerability exists due to insufficient validation of user-supplied input in libfsimage. A remote     guest can use pygrab to trigger stack-based buffer overflow and execute arbitrary code on the host system     (CVE-2023-34325)

  - The vulnerability exists due to missing IOMMU TLB flushing on x86/AMD systems. A malicious guest can     access memory not owned by the guest and escalate privileges on the system. (CVE-2023-34326)

  - The vulnerability exists due to improper validation of guest state when using Debug Masks in HVM vCPU. A     malicious guest can perform a denial of service (DoS) attack against the guest OS. (CVE-2023-34327)

  - The vulnerability exists due to improper validation of guest state in PV vCPU. A malicious guest place a     breakpoint over the live GDT and perform a denial of service (DoS) attack against the host.
    (CVE-2023-34328)

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 SLES15 / SLES_SAP15 host has packages installed that are affected by multiple vulnerabilities as referenced in the SUSE-SU-2023:4183-1 advisory.

  - The vulnerability exists due to a reachable assertion when handling negative quota values in C Xenstored.
    A malicious guest can craft a transaction that forces C Xenstored to check quota value and perform a     denial of service attack. (CVE-2023-34323)

  - The vulnerability exists due to insufficient validation of user-supplied input in libfsimage. A remote     guest can use pygrab to trigger stack-based buffer overflow and execute arbitrary code on the host system     (CVE-2023-34325)

  - The vulnerability exists due to missing IOMMU TLB flushing on x86/AMD systems. A malicious guest can     access memory not owned by the guest and escalate privileges on the system. (CVE-2023-34326)

  - The vulnerability exists due to improper validation of guest state when using Debug Masks in HVM vCPU. A     malicious guest can perform a denial of service (DoS) attack against the guest OS. (CVE-2023-34327)

  - The vulnerability exists due to improper validation of guest state in PV vCPU. A malicious guest place a     breakpoint over the live GDT and perform a denial of service (DoS) attack against the host.
    (CVE-2023-34328)

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 SLES12 / SLES_SAP12 host has packages installed that are affected by multiple vulnerabilities as referenced in the SUSE-SU-2023:4185-1 advisory.

  - The vulnerability exists due to a reachable assertion when handling negative quota values in C Xenstored.
    A malicious guest can craft a transaction that forces C Xenstored to check quota value and perform a     denial of service attack. (CVE-2023-34323)

  - The vulnerability exists due to insufficient validation of user-supplied input in libfsimage. A remote     guest can use pygrab to trigger stack-based buffer overflow and execute arbitrary code on the host system     (CVE-2023-34325)

  - The vulnerability exists due to missing IOMMU TLB flushing on x86/AMD systems. A malicious guest can     access memory not owned by the guest and escalate privileges on the system. (CVE-2023-34326)

  - The vulnerability exists due to improper validation of guest state when using Debug Masks in HVM vCPU. A     malicious guest can perform a denial of service (DoS) attack against the guest OS. (CVE-2023-34327)

  - The vulnerability exists due to improper validation of guest state in PV vCPU. A malicious guest place a     breakpoint over the live GDT and perform a denial of service (DoS) attack against the host.
    (CVE-2023-34328)

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-2023:4055-1 advisory.

  - The vulnerability exists due to a reachable assertion when handling negative quota values in C Xenstored.
    A malicious guest can craft a transaction that forces C Xenstored to check quota value and perform a     denial of service attack. (CVE-2023-34323)

  - The vulnerability exists due to insufficient validation of user-supplied input in libfsimage. A remote     guest can use pygrab to trigger stack-based buffer overflow and execute arbitrary code on the host system     (CVE-2023-34325)

  - The vulnerability exists due to missing IOMMU TLB flushing on x86/AMD systems. A malicious guest can     access memory not owned by the guest and escalate privileges on the system. (CVE-2023-34326)

  - The vulnerability exists due to improper validation of guest state when using Debug Masks in HVM vCPU. A     malicious guest can perform a denial of service (DoS) attack against the guest OS. (CVE-2023-34327)

  - The vulnerability exists due to improper validation of guest state in PV vCPU. A malicious guest place a     breakpoint over the live GDT and perform a denial of service (DoS) attack against the host.
    (CVE-2023-34328)

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-2023:4054-1 advisory.

  - The vulnerability exists due to a reachable assertion when handling negative quota values in C Xenstored.
    A malicious guest can craft a transaction that forces C Xenstored to check quota value and perform a     denial of service attack. (CVE-2023-34323)

  - The vulnerability exists due to insufficient validation of user-supplied input in libfsimage. A remote     guest can use pygrab to trigger stack-based buffer overflow and execute arbitrary code on the host system     (CVE-2023-34325)

  - The vulnerability exists due to missing IOMMU TLB flushing on x86/AMD systems. A malicious guest can     access memory not owned by the guest and escalate privileges on the system. (CVE-2023-34326)

  - The vulnerability exists due to improper validation of guest state when using Debug Masks in HVM vCPU. A     malicious guest can perform a denial of service (DoS) attack against the guest OS. (CVE-2023-34327)

  - The vulnerability exists due to improper validation of guest state in PV vCPU. A malicious guest place a     breakpoint over the live GDT and perform a denial of service (DoS) attack against the host.
    (CVE-2023-34328)

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

AMD CPUs since ~2014 have extensions to normal x86 debugging functionality. Xen supports guests using these extensions.

Unfortunately there are errors in Xen's handling of the guest state, leading to denials of service.

  - CVE-2023-34327 - An HVM vCPU can end up operating in the context of     a previous vCPUs debug mask state.

  - CVE-2023-34328 - A PV vCPU can place a breakpoint over the live GDT.
    This allows the PV vCPU to exploit XSA-156 / CVE-2015-8104 and lock     up the CPU entirely.

For CVE-2023-34327, any guest (PV or HVM) using Debug Masks normally for it's own purposes can cause incorrect behaviour in an unrelated HVM vCPU, most likely resulting in a guest crash.

For CVE-2023-34328, a buggy or malicious PV guest kernel can lock up the host.

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
185977	SUSE SLED15 / SLES15 / openSUSE 15 Security Update : xen (SUSE-SU-2023:4476-1)	Nessus	SuSE Local Security Checks	high
185975	SUSE SLED15 / SLES15 / openSUSE 15 Security Update : xen (SUSE-SU-2023:4475-1)	Nessus	SuSE Local Security Checks	high
185217	Fedora 39 : xen (2023-de338d9f37)	Nessus	Fedora Local Security Checks	high
183933	Fedora 37 : xen (2023-881672fdab)	Nessus	Fedora Local Security Checks	high
183905	Fedora 38 : xen (2023-a4c606585e)	Nessus	Fedora Local Security Checks	high
183863	SUSE SLES15 Security Update : xen (SUSE-SU-2023:4184-1)	Nessus	SuSE Local Security Checks	high
183861	SUSE SLES15 Security Update : xen (SUSE-SU-2023:4174-1)	Nessus	SuSE Local Security Checks	high
183860	SUSE SLES15 Security Update : xen (SUSE-SU-2023:4183-1)	Nessus	SuSE Local Security Checks	high
183858	SUSE SLES12 Security Update : xen (SUSE-SU-2023:4185-1)	Nessus	SuSE Local Security Checks	high
183015	SUSE SLED15 / SLES15 / openSUSE 15 Security Update : xen (SUSE-SU-2023:4055-1)	Nessus	SuSE Local Security Checks	high
183012	SUSE SLED15 / SLES15 / openSUSE 15 Security Update : xen (SUSE-SU-2023:4054-1)	Nessus	SuSE Local Security Checks	high
182973	Xen: x86/AMD: Debug Mask handling (XSA-444)	Nessus	Misc.	medium

Detections

Analytics

CVE-2023-34327

medium

Tenable Plugins

high

high

high

high

high

high

high

high

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high

medium