ESB-2018.1575 - [Ubuntu] linux kernel: Multiple vulnerabilities 2018-05-23

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             AUSCERT External Security Bulletin Redistribution

                    Linux kernel (HWE) vulnerabilities
                                23 May 2018


        AusCERT Security Bulletin Summary

Product:           linux-hwe
Publisher:         Ubuntu
Operating System:  Ubuntu
Impact/Access:     Execute Arbitrary Code/Commands -- Remote/Unauthenticated
                   Access Privileged Data          -- Existing Account      
                   Denial of Service               -- Remote/Unauthenticated
Resolution:        Patch/Upgrade
CVE Names:         CVE-2018-8822 CVE-2018-3639 CVE-2017-18208
                   CVE-2017-18203 CVE-2017-17975 CVE-2017-17449

Reference:         ASB-2018.0121

Original Bulletin:

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USN-3653-2: Linux kernel (HWE) vulnerabilities

22 May 2018

linux-hwe, linux-azure, linux-gcp, linux-oem vulnerabilities

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

  o Ubuntu 16.04 LTS


Several security issues were addressed in the Linux kernel.

Software Description

  o linux-azure - Linux kernel for Microsoft Azure Cloud systems
  o linux-gcp - Linux kernel for Google Cloud Platform (GCP) systems
  o linux-hwe - Linux hardware enablement (HWE) kernel
  o linux-oem - Linux kernel for OEM processors


USN-3653-1 fixed vulnerabilities and added mitigations in the Linux kernel for
Ubuntu 17.10. This update provides the corresponding updates for the Linux
Hardware Enablement (HWE) kernel from Ubuntu 17.10 for Ubuntu 16.04 LTS.

Jann Horn and Ken Johnson discovered that microprocessors utilizing speculative
execution of a memory read may allow unauthorized memory reads via a
sidechannel attack. This flaw is known as Spectre Variant 4. A local attacker
could use this to expose sensitive information, including kernel memory.

It was discovered that the netlink subsystem in the Linux kernel did not
properly restrict observations of netlink messages to the appropriate net
namespace. A local attacker could use this to expose sensitive information
(kernel netlink traffic). (CVE-2017-17449)

Tuba Yavuz discovered that a double-free error existed in the USBTV007 driver
of the Linux kernel. A local attacker could use this to cause a denial of
service (system crash) or possibly execute arbitrary code. (CVE-2017-17975)

It was discovered that a race condition existed in the Device Mapper component
of the Linux kernel. A local attacker could use this to cause a denial of
service (system crash). (CVE-2017-18203)

It was discovered that an infinite loop could occur in the madvise(2)
implementation in the Linux kernel in certain circumstances. A local attacker
could use this to cause a denial of service (system hang). (CVE-2017-18208)

Silvio Cesare discovered a buffer overwrite existed in the NCPFS implementation
in the Linux kernel. A remote attacker controlling a malicious NCPFS server
could use this to cause a denial of service (system crash) or possibly execute
arbitrary code. (CVE-2018-8822)

Update instructions

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

Ubuntu 16.04 LTS
    linux-image-4.13.0-1017-gcp - 4.13.0-1017.21
    linux-image-4.13.0-1018-azure - 4.13.0-1018.21
    linux-image-4.13.0-1028-oem - 4.13.0-1028.31
    linux-image-4.13.0-43-generic - 4.13.0-43.48~16.04.1
    linux-image-4.13.0-43-generic-lpae - 4.13.0-43.48~16.04.1
    linux-image-4.13.0-43-lowlatency - 4.13.0-43.48~16.04.1
    linux-image-azure -
    linux-image-gcp -
    linux-image-generic-hwe-16.04 -
    linux-image-generic-lpae-hwe-16.04 -
    linux-image-gke -
    linux-image-lowlatency-hwe-16.04 -
    linux-image-oem -

To update your system, please follow these instructions: https://

Please note that fully mitigating CVE-2018-3639 (Spectre Variant 4) may require
corresponding processor microcode/firmware updates or, in virtual environments,
hypervisor updates. On i386 and amd64 architectures, the SSBD feature is
required to enable the kernel mitigations. BIOS vendors will be making updates
available for Intel processors that implement SSBD and Ubuntu is working with
Intel to provide future microcode updates. Ubuntu users with a processor from a
different vendor should contact the vendor to identify necessary firmware
updates. Ubuntu provided corresponding QEMU updates for users of self-hosted
virtual environments in USN 3651-1. Ubuntu users in cloud environments should
contact the cloud provider to confirm that the hypervisor has been updated to
expose the new CPU features to virtual machines.


  o USN-3653-1
  o CVE-2017-17449
  o CVE-2017-17975
  o CVE-2017-18203
  o CVE-2017-18208
  o CVE-2018-3639
  o CVE-2018-8822

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