A certain Red Hat patch to the KVM subsystem in the kernel package before 2.6.32-358.11.1.el6 on Red Hat Enterprise Linux (RHEL) 6 does not properly implement the PV EOI feature, which allows guest OS users to cause a denial of service (host OS crash) by leveraging a time window during which interrupts are disabled but copy_to_user function calls are possible.

An updated rhev-hypervisor6 package that fixes two security issues and various bugs is now available.

The Red Hat Security Response Team has rated this update as having important security impact. Common Vulnerability Scoring System (CVSS) base scores, which give detailed severity ratings, are available for each vulnerability from the CVE links in the References section.

The rhev-hypervisor6 package provides a Red Hat Enterprise Virtualization Hypervisor ISO disk image. The Red Hat Enterprise Virtualization Hypervisor is a dedicated Kernel-based Virtual Machine (KVM) hypervisor. It includes everything necessary to run and manage virtual machines: A subset of the Red Hat Enterprise Linux operating environment and the Red Hat Enterprise Virtualization Agent.

Note: Red Hat Enterprise Virtualization Hypervisor is only available for the Intel 64 and AMD64 architectures with virtualization extensions.

A flaw was found in the way KVM initialized a guest's registered pv_eoi (paravirtualized end-of-interrupt) indication flag when entering the guest. An unprivileged guest user could potentially use this flaw to crash the host. (CVE-2013-1935)

A flaw was found in the way unexpected fields in guestInfo dictionaries were processed. A privileged guest user could potentially use this flaw to make the host the guest is running on unavailable to the management server. (CVE-2013-0167)

Red Hat would like to thank IBM for reporting the CVE-2013-1935 issue.
The CVE-2013-0167 issue was discovered by Dan Kenigsberg of the Red Hat Enterprise Virtualization team.

This updated package provides updated components that include fixes for various security issues. These issues have no security impact on Red Hat Enterprise Virtualization Hypervisor itself, however. The security fixes included in this update address the following CVE numbers :

CVE-2013-1962 (libvirt issue)

CVE-2013-2017 and CVE-2013-1943 (kernel issues)

CVE-2012-6137 (subscription-manager issue)

This update also contains the fixes from the following errata :

* vdsm: RHSA-2013:0886, which adds support for Red Hat Enterprise Virtualization 3.2 clusters.

* ovirt-node: RHBA-2013:0908

Upgrade Note: If you upgrade the Red Hat Enterprise Virtualization Hypervisor through the 3.2 Manager administration portal, the Host may appear with the status of 'Install Failed'. If this happens, place the host into maintenance mode, then activate it again to get the host back to an 'Up' state.

Users of the Red Hat Enterprise Virtualization Hypervisor are advised to upgrade to this updated package, which corrects these issues.

The remote Oracle Linux 6 host has packages installed that are affected by multiple vulnerabilities as referenced in the ELSA-2013-0911 advisory.

  - A certain Red Hat patch to the KVM subsystem in the kernel package before 2.6.32-358.11.1.el6 on Red Hat     Enterprise Linux (RHEL) 6 does not properly implement the PV EOI feature, which allows guest OS users to     cause a denial of service (host OS crash) by leveraging a time window during which interrupts are disabled     but copy_to_user function calls are possible. (CVE-2013-1935)

  - The KVM subsystem in the Linux kernel before 3.0 does not check whether kernel addresses are specified     during allocation of memory slots for use in a guest's physical address space, which allows local users to     gain privileges or obtain sensitive information from kernel memory via a crafted application, related to     arch/x86/kvm/paging_tmpl.h and virt/kvm/kvm_main.c. (CVE-2013-1943)

  - The veth (aka virtual Ethernet) driver in the Linux kernel before 2.6.34 does not properly manage skbs     during congestion, which allows remote attackers to cause a denial of service (system crash) by leveraging     lack of skb consumption in conjunction with a double-free error. (CVE-2013-2017)

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

Updated kernel packages that fix three security issues, several bugs, and add one enhancement are now available for Red Hat Enterprise Linux 6.

The Red Hat Security Response Team has rated this update as having important security impact. Common Vulnerability Scoring System (CVSS) base scores, which give detailed severity ratings, are available for each vulnerability from the CVE links in the References section.

The kernel packages contain the Linux kernel, the core of any Linux operating system.

This update fixes the following security issues :

* A flaw was found in the way KVM (Kernel-based Virtual Machine) initialized a guest's registered pv_eoi (paravirtualized end-of-interrupt) indication flag when entering the guest. An unprivileged guest user could potentially use this flaw to crash the host. (CVE-2013-1935, Important)

* A missing sanity check was found in the kvm_set_memory_region() function in KVM, allowing a user-space process to register memory regions pointing to the kernel address space. A local, unprivileged user could use this flaw to escalate their privileges. (CVE-2013-1943, Important)

* A double free flaw was found in the Linux kernel's Virtual Ethernet Tunnel driver (veth). A remote attacker could possibly use this flaw to crash a target system. (CVE-2013-2017, Moderate)

Red Hat would like to thank IBM for reporting the CVE-2013-1935 issue and Atzm WATANABE of Stratosphere Inc. for reporting the CVE-2013-2017 issue. The CVE-2013-1943 issue was discovered by Michael S. Tsirkin of Red Hat.

This update also fixes several bugs and adds one enhancement.
Documentation for these changes will be available shortly from the Technical Notes document linked to in the References section.

Users should upgrade to these updated packages, which contain backported patches to correct these issues and add this enhancement.
The system must be rebooted for this update to take effect.

This update fixes the following security issues :

  - A flaw was found in the way KVM (Kernel-based Virtual     Machine) initialized a guest's registered pv_eoi     (paravirtualized end-of-interrupt) indication flag when     entering the guest. An unprivileged guest user could     potentially use this flaw to crash the host.
    (CVE-2013-1935, Important)

  - A missing sanity check was found in the     kvm_set_memory_region() function in KVM, allowing a     user-space process to register memory regions pointing     to the kernel address space. A local, unprivileged user     could use this flaw to escalate their privileges.
    (CVE-2013-1943, Important)

  - A double free flaw was found in the Linux kernel's     Virtual Ethernet Tunnel driver (veth). A remote attacker     could possibly use this flaw to crash a target system.
    (CVE-2013-2017, Moderate)

The system must be rebooted for this update to take effect.

The remote Redhat Enterprise Linux 6 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2013:0911 advisory.

    The kernel packages contain the Linux kernel, the core of any Linux     operating system.

    This update fixes the following security issues:

    * A flaw was found in the way KVM (Kernel-based Virtual Machine)     initialized a guest's registered pv_eoi (paravirtualized end-of-interrupt)     indication flag when entering the guest. An unprivileged guest user could     potentially use this flaw to crash the host. (CVE-2013-1935, Important)

    * A missing sanity check was found in the kvm_set_memory_region() function     in KVM, allowing a user-space process to register memory regions pointing     to the kernel address space. A local, unprivileged user could use this flaw     to escalate their privileges. (CVE-2013-1943, Important)

    * A double free flaw was found in the Linux kernel's Virtual Ethernet     Tunnel driver (veth). A remote attacker could possibly use this flaw to     crash a target system. (CVE-2013-2017, Moderate)

    Red Hat would like to thank IBM for reporting the CVE-2013-1935 issue and     Atzm WATANABE of Stratosphere Inc. for reporting the CVE-2013-2017 issue.
    The CVE-2013-1943 issue was discovered by Michael S. Tsirkin of Red Hat.

    This update also fixes several bugs and adds one enhancement. Documentation     for these changes will be available shortly from the Technical Notes     document linked to in the References section.

    Users should upgrade to these updated packages, which contain backported     patches to correct these issues and add this enhancement. The system must     be rebooted for this update to take effect.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise 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.

ID	Name	Product	Family	Severity
78961	RHEL 6 : rhev-hypervisor6 (RHSA-2013:0907)	Nessus	Red Hat Local Security Checks	medium
68834	Oracle Linux 6 : kernel (ELSA-2013-0911)	Nessus	Oracle Linux Local Security Checks	high
66887	CentOS 6 : kernel (CESA-2013:0911)	Nessus	CentOS Local Security Checks	high
66884	Scientific Linux Security Update : kernel on SL6.x i386/x86_64 (20130610)	Nessus	Scientific Linux Local Security Checks	high
66853	RHEL 6 : kernel (RHSA-2013:0911)	Nessus	Red Hat Local Security Checks	high

Detections

Analytics

CVE-2013-1935

critical

Tenable Plugins

medium

high

high

high

high