The hvm_set_callback_via function in arch/x86/hvm/irq.c in Xen 4.6 does not limit the number of printk console messages when logging the new callback method, which allows local HVM guest OS users to cause a denial of service via a large number of changes to the callback method (HVM_PARAM_CALLBACK_IRQ).

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

  - The PV superpage functionality in arch/x86/mm.c in Xen 3.4.0, 3.4.1, and 4.1.x through 4.6.x allows local
    PV guests to obtain sensitive information, cause a denial of service, gain privileges, or have unspecified
    other impact via a crafted page identifier (MFN) to the (1) MMUEXT_MARK_SUPER or (2) MMUEXT_UNMARK_SUPER
    sub-op in the HYPERVISOR_mmuext_op hypercall or (3) unknown vectors related to page table updates.
    (CVE-2016-1570)

  - The memory_exchange function in common/memory.c in Xen 3.2.x through 4.6.x does not properly hand back
    pages to a domain, which might allow guest OS administrators to cause a denial of service (host crash) via
    unspecified vectors related to domain teardown. (CVE-2015-8339)

  - The memory_exchange function in common/memory.c in Xen 3.2.x through 4.6.x does not properly release
    locks, which might allow guest OS administrators to cause a denial of service (deadlock or host crash) via
    unspecified vectors, related to XENMEM_exchange error handling. (CVE-2015-8340)

  - The libxl toolstack library in Xen 4.1.x through 4.6.x does not properly release mappings of files used as
    kernels and initial ramdisks when managing multiple domains in the same process, which allows attackers to
    cause a denial of service (memory and disk consumption) by starting domains. (CVE-2015-8341)

  - Xen, when used on a system providing PV backends, allows local guest OS administrators to cause a denial
    of service (host OS crash) or gain privileges by writing to memory shared between the frontend and
    backend, aka a double fetch vulnerability. (CVE-2015-8550)

This security update fixes a number of security issues in Xen in wheezy.

For Debian 7 'Wheezy', these problems have been fixed in version 4.1.6.1-1+deb7u1.

We recommend that you upgrade your libidn packages.

CVE-2015-2752

The XEN_DOMCTL_memory_mapping hypercall in Xen 3.2.x through 4.5.x, when using a PCI passthrough device, is not preemptable, which allows local x86 HVM domain users to cause a denial of service (host CPU consumption) via a crafted request to the device model (qemu-dm).

CVE-2015-2756

QEMU, as used in Xen 3.3.x through 4.5.x, does not properly restrict access to PCI command registers, which might allow local HVM guest users to cause a denial of service (non-maskable interrupt and host crash) by disabling the (1) memory or (2) I/O decoding for a PCI Express device and then accessing the device, which triggers an Unsupported Request (UR) response.

CVE-2015-5165

The C+ mode offload emulation in the RTL8139 network card device model in QEMU, as used in Xen 4.5.x and earlier, allows remote attackers to read process heap memory via unspecified vectors.

CVE-2015-5307

The KVM subsystem in the Linux kernel through 4.2.6, and Xen 4.3.x through 4.6.x, allows guest OS users to cause a denial of service (host OS panic or hang) by triggering many #AC (aka Alignment Check) exceptions, related to svm.c and vmx.c.

CVE-2015-7969

Multiple memory leaks in Xen 4.0 through 4.6.x allow local guest administrators or domains with certain permission to cause a denial of service (memory consumption) via a large number of 'teardowns' of domains with the vcpu pointer array allocated using the (1) XEN_DOMCTL_max_vcpus hypercall or the xenoprofile state vcpu pointer array allocated using the (2) XENOPROF_get_buffer or (3) XENOPROF_set_passive hypercall.

CVE-2015-7970

The p2m_pod_emergency_sweep function in arch/x86/mm/p2m-pod.c in Xen 3.4.x, 3.5.x, and 3.6.x is not preemptible, which allows local x86 HVM guest administrators to cause a denial of service (CPU consumption and possibly reboot) via crafted memory contents that triggers a 'time-consuming linear scan,' related to Populate-on-Demand.

CVE-2015-7971

Xen 3.2.x through 4.6.x does not limit the number of printk console messages when logging certain pmu and profiling hypercalls, which allows local guests to cause a denial of service via a sequence of crafted (1) HYPERCALL_xenoprof_op hypercalls, which are not properly handled in the do_xenoprof_op function in common/xenoprof.c, or (2) HYPERVISOR_xenpmu_op hypercalls, which are not properly handled in the do_xenpmu_op function in arch/x86/cpu/vpmu.c.

CVE-2015-7972

The (1) libxl_set_memory_target function in tools/libxl/libxl.c and (2) libxl__build_post function in tools/libxl/libxl_dom.c in Xen 3.4.x through 4.6.x do not properly calculate the balloon size when using the populate-on-demand (PoD) system, which allows local HVM guest users to cause a denial of service (guest crash) via unspecified vectors related to 'heavy memory pressure.'

CVE-2015-8104

The KVM subsystem in the Linux kernel through 4.2.6, and Xen 4.3.x through 4.6.x, allows guest OS users to cause a denial of service (host OS panic or hang) by triggering many #DB (aka Debug) exceptions, related to svm.c.

CVE-2015-8339

The memory_exchange function in common/memory.c in Xen 3.2.x through 4.6.x does not properly hand back pages to a domain, which might allow guest OS administrators to cause a denial of service (host crash) via unspecified vectors related to domain teardown.

CVE-2015-8340

The memory_exchange function in common/memory.c in Xen 3.2.x through 4.6.x does not properly release locks, which might allow guest OS administrators to cause a denial of service (deadlock or host crash) via unspecified vectors, related to XENMEM_exchange error handling.

CVE-2015-8550

Xen, when used on a system providing PV backends, allows local guest OS administrators to cause a denial of service (host OS crash) or gain privileges by writing to memory shared between the frontend and backend, aka a double fetch vulnerability.

CVE-2015-8554

Buffer overflow in hw/pt-msi.c in Xen 4.6.x and earlier, when using the qemu-xen-traditional (aka qemu-dm) device model, allows local x86 HVM guest administrators to gain privileges by leveraging a system with access to a passed-through MSI-X capable physical PCI device and MSI-X table entries, related to a 'write path.'

CVE-2015-8555

Xen 4.6.x, 4.5.x, 4.4.x, 4.3.x, and earlier do not initialize x86 FPU stack and XMM registers when XSAVE/XRSTOR are not used to manage guest extended register state, which allows local guest domains to obtain sensitive information from other domains via unspecified vectors.

CVE-2015-8615

The hvm_set_callback_via function in arch/x86/hvm/irq.c in Xen 4.6 does not limit the number of printk console messages when logging the new callback method, which allows local HVM guest OS users to cause a denial of service via a large number of changes to the callback method (HVM_PARAM_CALLBACK_IRQ).

CVE-2016-1570

The PV superpage functionality in arch/x86/mm.c in Xen 3.4.0, 3.4.1, and 4.1.x through 4.6.x allows local PV guests to obtain sensitive information, cause a denial of service, gain privileges, or have unspecified other impact via a crafted page identifier (MFN) to the (1) MMUEXT_MARK_SUPER or (2) MMUEXT_UNMARK_SUPER sub-op in the HYPERVISOR_mmuext_op hypercall or (3) unknown vectors related to page table updates.

CVE-2016-1571

The paging_invlpg function in include/asm-x86/paging.h in Xen 3.3.x through 4.6.x, when using shadow mode paging or nested virtualization is enabled, allows local HVM guest users to cause a denial of service (host crash) via a non-canonical guest address in an INVVPID instruction, which triggers a hypervisor bug check.

CVE-2016-2270

Xen 4.6.x and earlier allows local guest administrators to cause a denial of service (host reboot) via vectors related to multiple mappings of MMIO pages with different cachability settings.

CVE-2016-2271

VMX in Xen 4.6.x and earlier, when using an Intel or Cyrix CPU, allows local HVM guest users to cause a denial of service (guest crash) via vectors related to a non-canonical RIP.

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

ID	Name	Product	Family	Severity
401058	Alpine: multiple xen packages: security update to 4.6.0-r4 (deprecated)	Tenable Cloud Security	Alpine Linux Local Security Checks	high
401058	Alpine: multiple xen packages: security update to 4.6.0-r4 (deprecated)	Tenable Self-Hosted Container Security	Alpine Linux Local Security Checks	high
91198	Debian DLA-479-1 : xen security update	Nessus	Debian Local Security Checks	high

Detections

Analytics

CVE-2015-8615

medium

Tenable Plugins

high

high

high