Buffer overflow in the vnc_refresh_server_surface function in the VNC display driver in QEMU before 2.4.0.1 allows guest users to cause a denial of service (heap memory corruption and process crash) or possibly execute arbitrary code on the host via unspecified vectors, related to refreshing the server display surface.

redhat RHSA-2015:1772: RHSA-2015:1772: qemu-kvm-rhev security update (Important)

Updated qemu-kvm-rhev packages that fix one security issue are now available for Red Hat Enterprise Virtualization Hypervisor 7.

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.

KVM (Kernel-based Virtual Machine) is a full virtualization solution for Linux on AMD64 and Intel 64 systems. The qemu-kvm-rhev package provides the user-space component for running virtual machines using KVM.

A heap-based buffer overflow issue was found in the QEMU emulator's VNC display driver. It could occur while refreshing the VNC server's display surface using the vnc_refresh_server_surface() routine. A privileged guest user could use this flaw to corrupt the heap memory and crash the QEMU process instance, or to potentially use it to execute arbitrary code on the host. (CVE-2015-5225)

Red Hat would like to thank Mr Qinghao Tang from QIHU 360 Inc. and Mr Zuozhi from Alibaba Inc. for reporting this issue.

All qemu-kvm-rhev users are advised to upgrade to these updated packages, which contain a backported patch to correct this issue.
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 host is affected by the vulnerability described in GLSA-201602-01 (QEMU: Multiple vulnerabilities)

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

    A remote attacker might cause a Denial of Service or gain escalated       privileges from a guest VM.
  Workaround :

    There is no known workaround at this time.

Prasad J Pandit, Red Hat Product Security Team, reports :

Qemu emulator built with the VNC display driver support is vulnerable to a buffer overflow flaw leading to a heap memory corruption issue.
It could occur while refreshing the server display surface via routine vnc_refresh_server_surface().

A privileged guest user could use this flaw to corrupt the heap memory and crash the Qemu process instance OR potentially use it to execute arbitrary code on the host.

- CVE-2015-6815: net: e1000: infinite loop issue (bz     #1260225) * CVE-2015-6855: ide: divide by zero issue (bz     #1261793) * CVE-2015-5278: Infinite loop in     ne2000_receive() (bz #1263284) * CVE-2015-5279: Heap     overflow vulnerability in ne2000_receive() (bz #1263287)
    * Make block copy more stable (bz #1264416) * Fix hang     at start of live merge for large images (bz #1262901)
    ---- * CVE-2015-5225: heap memory corruption in     vnc_refresh_server_surface (bz #1255899)

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

Fix typo causing qemu-img to link against entire world (bz #1260996)
---- * CVE-2015-5225: heap memory corruption in vnc_refresh_server_surface (bz #1255899)

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

- CVE-2015-5225: heap memory corruption in     vnc_refresh_server_surface (bz #1255899)

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

Several vulnerabilities were discovered in qemu, a fast processor emulator.

  - CVE-2015-3214     Matt Tait of Google's Project Zero security team     discovered a flaw in the QEMU i8254 PIT emulation. A     privileged guest user in a guest with QEMU PIT emulation     enabled could potentially use this flaw to execute     arbitrary code on the host with the privileges of the     hosting QEMU process.

  - CVE-2015-5154     Kevin Wolf of Red Hat discovered a heap buffer overflow     flaw in the IDE subsystem in QEMU while processing     certain ATAPI commands. A privileged guest user in a     guest with the CDROM drive enabled could potentially use     this flaw to execute arbitrary code on the host with the     privileges of the hosting QEMU process.

  - CVE-2015-5165     Donghai Zhu discovered that the QEMU model of the     RTL8139 network card did not sufficiently validate     inputs in the C+ mode offload emulation, allowing a     malicious guest to read uninitialized memory from the     QEMU process's heap.

  - CVE-2015-5225     Mr Qinghao Tang from QIHU 360 Inc. and Mr Zuozhi from     Alibaba Inc discovered a buffer overflow flaw in the VNC     display driver leading to heap memory corruption. A     privileged guest user could use this flaw to mount a     denial of service (QEMU process crash), or potentially     to execute arbitrary code on the host with the     privileges of the hosting QEMU process.

  - CVE-2015-5745     A buffer overflow vulnerability was discovered in the     way QEMU handles the virtio-serial device. A malicious     guest could use this flaw to mount a denial of service     (QEMU process crash).

It was discovered that QEMU incorrectly handled a PRDT with zero complete sectors in the IDE functionality. A malicious guest could possibly use this issue to cause a denial of service. This issue only affected Ubuntu 12.04 LTS and Ubuntu 14.04 LTS. (CVE-2014-9718)

Donghai Zhu discovered that QEMU incorrectly handled the RTL8139 driver. A malicious guest could possibly use this issue to read sensitive information from arbitrary host memory. (CVE-2015-5165)

Donghai Zhu discovered that QEMU incorrectly handled unplugging emulated block devices. A malicious guest could use this issue to cause a denial of service, or possibly execute arbitrary code on the host as the user running the QEMU process. In the default installation, when QEMU is used with libvirt, attackers would be isolated by the libvirt AppArmor profile. This issue only affected Ubuntu 15.04. (CVE-2015-5166)

Qinghao Tang and Mr. Zuozhi discovered that QEMU incorrectly handled memory in the VNC display driver. A malicious guest could use this issue to cause a denial of service, or possibly execute arbitrary code on the host as the user running the QEMU process. In the default installation, when QEMU is used with libvirt, attackers would be isolated by the libvirt AppArmor profile. This issue only affected Ubuntu 15.04. (CVE-2015-5225)

It was discovered that QEMU incorrectly handled the virtio-serial device. A malicious guest could use this issue to cause a denial of service, or possibly execute arbitrary code on the host as the user running the QEMU process. In the default installation, when QEMU is used with libvirt, attackers would be isolated by the libvirt AppArmor profile. This issue only affected Ubuntu 14.04 LTS and Ubuntu 15.04.
(CVE-2015-5745).

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

ID	Name	Product	Family	Severity
117308	RHEL 7 : qemu-kvm-rhev (RHSA-2015:1837)	Nessus	Red Hat Local Security Checks	high
88587	GLSA-201602-01 : QEMU: Multiple vulnerabilities (Venom)	Nessus	Gentoo Local Security Checks	critical
87689	FreeBSD : qemu -- buffer overflow vulnerability in VNC (2b3b4c27-b0c7-11e5-8d13-bc5ff45d0f28)	Nessus	FreeBSD Local Security Checks	high
86332	Fedora 21 : qemu-2.1.3-11.fc21 (2015-16368)	Nessus	Fedora Local Security Checks	critical
86040	Fedora 22 : qemu-2.3.1-3.fc22 (2015-15364)	Nessus	Fedora Local Security Checks	high
85774	Fedora 23 : qemu-2.4.0-2.fc23 (2015-14783)	Nessus	Fedora Local Security Checks	high
85754	Debian DSA-3348-1 : qemu - security update	Nessus	Debian Local Security Checks	medium
85683	Ubuntu 14.04 LTS : QEMU vulnerabilities (USN-2724-1)	Nessus	Ubuntu Local Security Checks	medium

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