Ubuntu 14.04 LTS / 16.04 LTS / 17.10 : libvirt update (USN-3561-1) (Spectre)
Medium Nessus Plugin ID 106677
SynopsisThe remote Ubuntu host is missing one or more security-related patches.
DescriptionIt was discovered that microprocessors utilizing speculative execution and branch prediction may allow unauthorized memory reads via sidechannel attacks. This flaw is known as Spectre. An attacker in the guest could use this to expose sensitive guest information, including kernel memory.
This update allows libvirt to expose new CPU features added by microcode updates to guests. On amd64 and i386, new CPU models that match the updated microcode features were added with an -IBRS suffix.
Certain environments will require guests to be switched manually to the new CPU models after microcode updates have been applied to the host.
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.
SolutionUpdate the affected libvirt-bin and / or libvirt0 packages.