RHSA-2015:2696 - Security Advisory

Topic

Updated qemu-kvm-rhev packages that fix two security issues are now
available for Red Hat Enterprise Virtualization.

Red Hat Product Security 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.

Description

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 flaw was discovered in the way QEMU's AMD
PC-Net II Ethernet Controller emulation received certain packets in
loopback mode. A privileged user (with the CAP_SYS_RAWIO capability) inside
a guest could use this flaw to crash the host QEMU process (resulting in
denial of service) or, potentially, execute arbitrary code with privileges
of the host QEMU process. (CVE-2015-7504)

A buffer overflow flaw was found in the way QEMU's AMD PC-Net II emulation
validated certain received packets from a remote host in non-loopback mode.
A remote, unprivileged attacker could potentially use this flaw to execute
arbitrary code on the host with the privileges of the QEMU process.
Note that to exploit this flaw, the guest network interface must have a
large MTU limit. (CVE-2015-7512)

Red Hat would like to thank Qinghao Tang of QIHU 360 Marvel Team and Ling
Liu of Qihoo 360 Inc. for reporting the CVE-2015-7504 issue, and Ling Liu
of Qihoo 360 Inc. for reporting the CVE-2015-7512 issue. The CVE-2015-7512
issue was independently discovered by Jason Wang of Red Hat.

All qemu-kvm-rhev users are advised to upgrade to these updated packages,
which contain backported patches to correct these issues. 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.

Solution

Before applying this update, make sure all previously released errata
relevant to your system have been applied.

For details on how to apply this update, refer to:

https://access.redhat.com/articles/11258

Affected Products

• Red Hat Virtualization 3 for RHEL 6 x86_64

Fixes

• BZ - 1261461 - CVE-2015-7504 Qemu: net: pcnet: heap overflow vulnerability in pcnet_receive
• BZ - 1285061 - CVE-2015-7512 Qemu: net: pcnet: buffer overflow in non-loopback mode

CVEs

• CVE-2015-7512
• CVE-2015-7504

References

• https://access.redhat.com/security/updates/classification/#important