USN-3732-1: Linux kernel vulnerability

6 August 2018

linux, linux-aws, linux-azure, linux-gcp, linux-kvm, linux-oem, linux-raspi2 vulnerability

A security issue affects these releases of Ubuntu and its derivatives:

  • Ubuntu 18.04 LTS

Summary

The system could be made unavailable if it received specially crafted network traffic.

Software Description

  • linux - Linux kernel
  • linux-aws - Linux kernel for Amazon Web Services (AWS) systems
  • linux-azure - Linux kernel for Microsoft Azure Cloud systems
  • linux-gcp - Linux kernel for Google Cloud Platform (GCP) systems
  • linux-kvm - Linux kernel for cloud environments
  • linux-oem - Linux kernel for OEM processors
  • linux-raspi2 - Linux kernel for Raspberry Pi 2

Details

Juha-Matti Tilli discovered that the TCP implementation in the Linux kernel performed algorithmically expensive operations in some situations when handling incoming packets. A remote attacker could use this to cause a denial of service.

Update instructions

The problem can be corrected by updating your system to the following package versions:

Ubuntu 18.04 LTS
linux-image-4.15.0-1013-oem - 4.15.0-1013.16
linux-image-4.15.0-1015-gcp - 4.15.0-1015.15
linux-image-4.15.0-1017-aws - 4.15.0-1017.17
linux-image-4.15.0-1017-kvm - 4.15.0-1017.17
linux-image-4.15.0-1018-raspi2 - 4.15.0-1018.19
linux-image-4.15.0-1019-azure - 4.15.0-1019.19
linux-image-4.15.0-30-generic - 4.15.0-30.32
linux-image-4.15.0-30-generic-lpae - 4.15.0-30.32
linux-image-4.15.0-30-lowlatency - 4.15.0-30.32
linux-image-4.15.0-30-snapdragon - 4.15.0-30.32
linux-image-aws - 4.15.0.1017.17
linux-image-azure - 4.15.0.1019.19
linux-image-azure-edge - 4.15.0.1019.19
linux-image-gcp - 4.15.0.1015.17
linux-image-generic - 4.15.0.30.32
linux-image-generic-lpae - 4.15.0.30.32
linux-image-gke - 4.15.0.1015.17
linux-image-kvm - 4.15.0.1017.17
linux-image-lowlatency - 4.15.0.30.32
linux-image-oem - 4.15.0.1013.15
linux-image-raspi2 - 4.15.0.1018.16
linux-image-snapdragon - 4.15.0.30.32

To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.

After a standard system update you need to reboot your computer to make all the necessary changes.

ATTENTION: Due to an unavoidable ABI change the kernel updates have been given a new version number, which requires you to recompile and reinstall all third party kernel modules you might have installed. Unless you manually uninstalled the standard kernel metapackages (e.g. linux-generic, linux-generic-lts-RELEASE, linux-virtual, linux-powerpc), a standard system upgrade will automatically perform this as well.

References