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Important product update: Virtuozzo 7.0 Update 7 Hotfix 3 (7.0.7-461)

Issue date: 2018-05-30

Applies to: Virtuozzo 7.0

Virtuozzo Advisory ID: VZA-2018-037

1. Overview

The Hotfix 3 for Virtuozzo 7.0 Update 7 provides security and stability fixes.

2. Security Fixes

  • [Important] A flaw was found in the way the Linux kernel’s KVM hypervisor handled exceptions delivered after a stack switch operation via Mov SS or Pop SS instructions. During the stack switch operation, the processor did not deliver interrupts and exceptions, rather they are delivered once the first instruction after the stack switch is executed. An unprivileged KVM guest user could use this flaw to crash the guest or, potentially, escalate their privileges in the guest. (CVE-2018-1087)

  • [Important] 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. NOTE: This fix also requires CPU microcode/firmware updates and subscribers are advised to contact their hardware OEM vendors to receive the appropriate microcode/firmware for their processor. A kernel update, without the appropriate firmware/microcode updated for the processor, is insufficient to remediate this vulnerability. (CVE-2018-3639)

  • [Moderate] A flaw was found in the way the Linux kernel handled exceptions delivered after a stack switch operation via Mov SS or Pop SS instructions. During the stack switch operation, the processor did not deliver interrupts and exceptions, rather they are delivered once the first instruction after the stack switch is executed. An unprivileged system user could use this flaw to crash the system kernel resulting in the denial of service. (CVE-2018-8897)

3. Bug Fixes

  • The ‘ip’ tool could hang on netlink_recvmsg(). As a result, containers could fail to start. (PSBM-84191)

4. Installing the Update

Install the update by running ‘yum update’.

Dec 12, 2024
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