Synopsis
Important: microcode_ctl security update
Type/Severity
Security Advisory: Important
Topic
An update for microcode_ctl is now available for Red Hat Enterprise Linux 7.2 Advanced Update Support, Red Hat Enterprise Linux 7.2 Telco Extended Update Support, and Red Hat Enterprise Linux 7.2 Update Services for SAP Solutions.
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.
Description
The microcode_ctl packages provide microcode updates for Intel and AMD processors.
Security Fix(es):
- An industry-wide issue was found in the way many modern microprocessor designs have implemented speculative execution of instructions (a commonly used performance optimization). There are three primary variants of the issue which differ in the way the speculative execution can be exploited. Variant CVE-2017-5715 triggers the speculative execution by utilizing branch target injection. It relies on the presence of a precisely-defined instruction sequence in the privileged code as well as the fact that memory accesses may cause allocation 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 cross the syscall and guest/host boundaries and read privileged memory by conducting targeted cache side-channel attacks. (CVE-2017-5715)
Note: This is the microcode counterpart of the CVE-2017-5715 kernel mitigation.
Red Hat would like to thank Google Project Zero for reporting this issue.
Solution
For details on how to apply this update, which includes the changes described in this advisory, refer to:
https://access.redhat.com/articles/11258
Note: a system reboot is necessary for this update to take effect.
Affected Products
-
Red Hat Enterprise Linux Server - AUS 7.2 x86_64
-
Red Hat Enterprise Linux Server - TUS 7.2 x86_64
-
Red Hat Enterprise Linux Server - Update Services for SAP Solutions 7.2 x86_64
Fixes
- BZ - 1519780 - CVE-2017-5715 hw: cpu: speculative execution branch target injection
CVEs
(none)
References
Vulmon