RHSA-2018:1711 — Security Advisory

An update for rhev-hypervisor7 is now available for RHEV 3.X Hypervisor and Agents Extended Lifecycle Support for Red Hat Enterprise Linux 6 and RHEV 3.X Hypervisor and Agents Extended Lifecycle Support for Red Hat Enterprise Linux 7.

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

The rhev-hypervisor7 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.

Security Fix(es):

• An industry-wide issue was found in the way many modern microprocessor designs have implemented speculative execution of Load & Store instructions (a commonly used performance optimization). It relies on the presence of a precisely-defined instruction sequence in the privileged code as well as the fact that memory read from address to which a recent memory write has occurred may see an older value and subsequently cause an update into the microprocessor's data cache even for speculatively executed instructions that never actually commit (retire). As a result, an unprivileged attacker could use this flaw to read privileged memory by conducting targeted cache side-channel attacks. (CVE-2018-3639)

Note: This is the rhev-hypervisor7 side of the CVE-2018-3639 mitigation.

Red Hat would like to thank Ken Johnson (Microsoft Security Response Center) and Jann Horn (Google Project Zero) for reporting this issue.