An out-of-bounds memory access flaw was found in the way QEMU's virtual Floppy Disk Controller (FDC) handled FIFO buffer access while processing certain FDC commands. A privileged guest user could use this flaw to crash the guest or, potentially, execute arbitrary code on the host with the privileges of the host's QEMU process corresponding to the guest. (CVE-2015-3456)

After installing this update, shut down all running virtual machines.
Once all virtual machines have shut down, start them again for this update to take effect.

The remote OracleVM system is missing necessary patches to address critical security updates :

  - fdc: force the fifo access to be in bounds of the     allocated buffer During processing of certain commands     such as FD_CMD_READ_ID and     FD_CMD_DRIVE_SPECIFICATION_COMMAND the fifo memory     access could get out of bounds leading to memory     corruption with values coming from the guest. Fix this     by making sure that the index is always bounded by the     allocated memory. This is CVE-2015-3456.

    XSA-133 (CVE-2015-3456)

  - fdc: force the fifo access to be in bounds of the     allocated buffer During processing of certain commands     such as FD_CMD_READ_ID and     FD_CMD_DRIVE_SPECIFICATION_COMMAND the fifo memory     access could get out of bounds leading to memory     corruption with values coming from the guest. Fix this     by making sure that the index is always bounded by the     allocated memory. This is CVE-2015-3456.

    XSA-133 (CVE-2015-3456)

  - domctl: don't allow a toolstack domain to call     domain_pause on itself These DOMCTL subops were     accidentally declared safe for disaggregation in the     wake of XSA-77. This is XSA-127. (CVE-2015-2751)

  - xen: limit guest control of PCI command register     Otherwise the guest can abuse that control to cause e.g.
    PCIe Unsupported Request responses (by disabling memory     and/or I/O decoding and subsequently causing [CPU side]     accesses to the respective address ranges), which     (depending on system configuration) may be fatal to the     host. This is CVE-2015-2756 / XSA-126.

    Conflicts:
    tools/qemu-xen-traditional-dir/hw/pass-through.c     (CVE-2015-2756)

  - xen: limit guest control of PCI command register     Otherwise the guest can abuse that control to cause e.g.
    PCIe Unsupported Request responses (by disabling memory     and/or I/O decoding and subsequently causing [CPU side]     accesses to the respective address ranges), which     (depending on system configuration) may be fatal to the     host. This is CVE-2015-2756 / XSA-126. (CVE-2015-2756)

  - Limit XEN_DOMCTL_memory_mapping hypercall to only     process up to 64 GFNs (or less) Said hypercall for large     BARs can take quite a while. As such we can require that     the hypercall MUST break up the request in smaller     values. Another approach is to add preemption to it -     whether we do the preemption using     hypercall_create_continuation or returning EAGAIN to     userspace (and have it re-invocate the call) - either     way the issue we cannot easily solve is that in     'map_mmio_regions' if we encounter an error we MUST call     'unmap_mmio_regions' for the whole BAR region. Since the     preemption would re-use input fields such as nr_mfns,     first_gfn, first_mfn - we would lose the original values
    - and only undo what was done in the current round (i.e.
    ignoring anything that was done prior to earlier     preemptions). Unless we re-used the return value as     'EAGAIN|nr_mfns_done<<10' but that puts a limit (since     the return value is a long) on the amount of nr_mfns     that can provided. This patch sidesteps this problem by :

  - Setting an hard limit of nr_mfns having to be 64 or     less.

  - Toolstack adjusts correspondingly to the nr_mfn limit.

  - If the there is an error when adding the toolstack will     call the remove operation to remove the whole region.
    The need to break this hypercall down is for large BARs     can take more than the guest (initial domain usually)     time-slice. This has the negative result in that the     guest is locked out for a long duration and is unable to     act on any pending events. We also augment the code to     return zero if nr_mfns instead of trying to the     hypercall. Suggested-by: Jan Beulich 

    This is CVE-2015-2752 / XSA-125. (CVE-2015-2752)

Jason Geffner, CrowdStrike Senior Security Researcher reports :

VENOM, CVE-2015-3456, is a security vulnerability in the virtual floppy drive code used by many computer virtualization platforms. This vulnerability may allow an attacker to escape from the confines of an affected virtual machine (VM) guest and potentially obtain code-execution access to the host. Absent mitigation, this VM escape could open access to the host system and all other VMs running on that host, potentially giving adversaries significant elevated access to the host's local network and adjacent systems.

KVM was updated to fix a buffer overflow in the floppy drive emulation, which could be used to carry out denial of service attacks or potential code execution against the host. This vulnerability is also known as VENOM. (CVE-2015-3456)

Jason Geffner discovered a buffer overflow in the emulated floppy disk drive, resulting in the potential execution of arbitrary code. This only affects HVM guests.

qemu was updated to fix a security issue :

  - CVE-2015-3456: Fixed a buffer overflow in the floppy     drive emulation, which could be used to denial of     service attacks or potential code execution against the     host.

Updated rhev-hypervisor packages that fix one security issue are now available.

Red Hat Product Security has rated this update as having Important security impact. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available from the CVE link in the References section.

The rhev-hypervisor packages provide 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.

An out-of-bounds memory access flaw was found in the way QEMU's virtual Floppy Disk Controller (FDC) handled FIFO buffer access while processing certain FDC commands. A privileged guest user could use this flaw to crash the guest or, potentially, execute arbitrary code on the host with the privileges of the host's QEMU process corresponding to the guest. (CVE-2015-3456)

Red Hat would like to thank Jason Geffner of CrowdStrike for reporting this issue.

Users of the Red Hat Enterprise Virtualization Hypervisor are advised to upgrade to this updated package.

XEN was updated to fix two security issues and bugs.

Security issues fixed :

  - CVE-2015-3340: Xen did not initialize certain fields,     which allowed certain remote service domains to obtain     sensitive information from memory via a (1)     XEN_DOMCTL_gettscinfo or (2)     XEN_SYSCTL_getdomaininfolist request.

  - CVE-2015-2751: Xen, when using toolstack disaggregation,     allowed remote domains with partial management control     to cause a denial of service (host lock) via unspecified     domctl operations.

  - CVE-2015-2752: The XEN_DOMCTL_memory_mapping hypercall     in Xen, when using a PCI passthrough device, was not     preemptable, which allowed 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-2015-3456: Fixed a buffer overflow in the floppy     drive emulation, which could be used to denial of     service attacks or potential code execution against the     host.

Bugs fixed :

  - xentop: Fix memory leak on read failure

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.

The remote host is running a version of VirtualBox which is vulnerable to an out-of-bounds memory access flaw, which can cause a crash or execution of arbitrary code on the host.

The remote host is running a version of qemu-kvm which is vulnerable to an out-of-bounds memory access flaw, which can cause a crash or execution of arbitrary code on the host.

The remote host is running a version of xen which is vulnerable to an out-of-bounds memory access flaw, which can cause a crash or execution of arbitrary code on the host.

The remote host is running a version of qemu-kvm-rhev which is vulnerable to an out-of-bounds memory access flaw, which can cause a crash or execution of arbitrary code on the host.

The remote host is running a version of kvm which is vulnerable to an out-of-bounds memory access flaw, which can cause a crash or execution of arbitrary code on the host.

ID	Name	Product	Family	Published	Updated	Severity
83458	Scientific Linux Security Update : qemu-kvm on SL6.x i386/x86_64 (20150513) (Venom)	Nessus	Scientific Linux Local Security Checks	5/14/2015	9/28/2023	high
83482	OracleVM 3.3 : xen (OVMSA-2015-0057) (Venom)	Nessus	OracleVM Local Security Checks	5/15/2015	1/4/2021	high
83510	FreeBSD : qemu, xen and VirtualBox OSE -- possible VM escape and code execution ('VENOM') (2780e442-fc59-11e4-b18b-6805ca1d3bb1) (Venom)	Nessus	FreeBSD Local Security Checks	5/18/2015	9/28/2023	high
83515	SuSE 11.3 Security Update : KVM (SAT Patch Number 10672)	Nessus	SuSE Local Security Checks	5/18/2015	9/28/2023	high
83532	Debian DSA-3262-1 : xen - security update (Venom)	Nessus	Debian Local Security Checks	5/19/2015	9/28/2023	high
83533	openSUSE Security Update : qemu (openSUSE-2015-363) (Venom)	Nessus	SuSE Local Security Checks	5/19/2015	9/28/2023	high
83536	RHEL 7 : rhev-hypervisor (RHSA-2015:1011) (Venom)	Nessus	Red Hat Local Security Checks	5/19/2015	9/28/2023	high
83757	SUSE SLED12 / SLES12 Security Update : xen (SUSE-SU-2015:0923-1) (Venom)	Nessus	SuSE Local Security Checks	5/21/2015	9/28/2023	high
801944	VirtualBox < 4.3-4.3.28 Venom Vulnerability	Log Correlation Engine	Generic			high
801941	qemu-kvm < 1.5.3-86 el6 Venom Vulnerability	Log Correlation Engine	Generic			high
801939	xen < 3.0.3-146 Venom Vulnerability	Log Correlation Engine	Generic			high
801942	qemu-kvm-rhev < 2.1.2-23 el7 Venom Vulnerability	Log Correlation Engine	Generic			high
801940	qemu-kvm < 0.12.1.2-2.448 el6 Venom Vulnerability	Log Correlation Engine	Generic			high
801943	kvm < 83-272 el5+ Venom Vulnerability	Log Correlation Engine	Generic			high

Detections

Analytics

Plugins Search

high

high

high

high

high

high

high

high

high

high

high

high

high

high