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Important product update: Fixes for Meltdown and Spectre exploits in virtual machines; Virtuozzo 6.0 Update 12 Hotfix 21 (6.0.12-3698)

Issue date: 2018-02-01

Applies to: Virtuozzo 6.0

Virtuozzo Advisory ID: VZA-2018-006

1. Overview

Hotfix 21 for Virtuozzo 6.0 Update 12 provides fixes for Meltdown and Spectre exploits in virtual machines as well as stability and usability bug fixes. NOTE: For clusters with CPU pools, follow the instructions in KB article #2919459.

2. Security Fixes

  • [Important] 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)

  • [Important] CVE-2017-5753 triggers the speculative execution by performing a bounds-check bypass. 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 boundary and read privileged memory by conducting targeted cache side-channel attacks. (CVE-2017-5753)

  • [Important] CVE-2017-5754 relies on the fact that, on impacted microprocessors, during speculative execution of instruction permission faults, exception generation triggered by a faulting access is suppressed until the retirement of the whole instruction block. In a combination with the fact that memory accesses may populate the cache even when the block is being dropped and never committed (executed), an unprivileged local attacker could use this flaw to read privileged (kernel space) memory by conducting targeted cache side-channel attacks. (CVE-2017-5754)

3. Bug Fixes

  • Rebooting the node while a backup of a VM was being created could make that VM unbootable. (PSBM-39311)

  • A Windows 10 VM could crash after the installation of Creators Update (1703). (PSBM-76329)

  • Fixes for Meltdown and Spectre exploits in virtual machines. (PSBM-80320)

  • Uninstalling guest tools could make VM unbootable. (PSBM-80327)

  • Guest tools could not be stopped gracefully in guests with ‘systemd’. (PSBM-80976)

4. Installing the Update

Install the update by running ‘yum update’.

Dec 12, 2024
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