Important kernel security update: CVE-2018-1087 and other; Virtuozzo ReadyKernel patch 51.1 for Virtuozzo 7.0.3 to 7.0.7 HF2

Issue date: 2018-05-17

Applies to: Virtuozzo 7.0

Virtuozzo Advisory ID: VZA-2018-030

1. Overview

The cumulative Virtuozzo ReadyKernel patch was updated with security fixes. The patch applies to all supported Virtuozzo 7.0 kernels.

2. Security Fixes

  • [Important] A flaw was found in how KVM handled exceptions delivered after Mov SS or Pop SS instructions have encountered a breakpoint. As a result, exceptions passed to the guest kernel could have wrong values on the stack. An unprivileged KVM guest user could use this flaw to crash the guest kernel or, potentially, escalate their privileges in the guest system. (CVE-2018-1087)

  • [Important] The implementation of ptrace in the kernel does not handle errors correctly when working with the debug registers. As a result, the hardware breakpoints could become corrupted. An unprivileged user could exploit this flaw to crash the kernel resulting in a denial-of-service, or, potentially, to escalate their privileges in the system. (CVE-2018-1000199)

3. Installing the Update

Download, install, and instantly apply the patch to the current kernel by running ‘readykernel update’.