Executive Summary

Summary
Title Linux kernel (HWE) vulnerabilities
Informations
Name USN-3836-2 First vendor Publication 2018-12-04
Vendor Ubuntu Last vendor Modification 2018-12-04
Severity (Vendor) N/A Revision N/A

Security-Database Scoring CVSS v3

Cvss vector : N/A
Overall CVSS Score NA
Base Score NA Environmental Score NA
impact SubScore NA Temporal Score NA
Exploitabality Sub Score NA
 
Calculate full CVSS 3.0 Vectors scores

Security-Database Scoring CVSS v2

Cvss vector : (AV:L/AC:M/Au:N/C:P/I:P/A:P)
Cvss Base Score 4.4 Attack Range Local
Cvss Impact Score 6.4 Attack Complexity Medium
Cvss Expoit Score 3.4 Authentication None Required
Calculate full CVSS 2.0 Vectors scores

Detail

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

- Ubuntu 16.04 LTS

Summary:

Several security issues were fixed in the Linux kernel.

Software Description: - linux-gcp: Linux kernel for Google Cloud Platform (GCP) systems - linux-hwe: Linux hardware enablement (HWE) kernel

Details:

USN-3836-1 fixed vulnerabilities in the Linux kernel for Ubuntu 18.04 LTS. This update provides the corresponding updates for the Linux Hardware Enablement (HWE) kernel from Ubuntu 18.04 LTS for Ubuntu 16.04 LTS.

Jann Horn discovered that the Linux kernel mishandles mapping UID or GID ranges inside nested user namespaces in some situations. A local attacker could use this to bypass access controls on resources outside the namespace. (CVE-2018-18955)

Philipp Wendler discovered that the overlayfs implementation in the Linux kernel did not properly verify the directory contents permissions from within a unprivileged user namespace. A local attacker could use this to expose sensitive information (protected file names). (CVE-2018-6559)

Update instructions:

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

Ubuntu 16.04 LTS:
linux-image-4.15.0-1025-gcp 4.15.0-1025.26~16.04.1
linux-image-4.15.0-42-generic 4.15.0-42.45~16.04.1
linux-image-4.15.0-42-generic-lpae 4.15.0-42.45~16.04.1
linux-image-4.15.0-42-lowlatency 4.15.0-42.45~16.04.1
linux-image-gcp 4.15.0.1025.39
linux-image-generic-hwe-16.04 4.15.0.42.63
linux-image-generic-lpae-hwe-16.04 4.15.0.42.63
linux-image-gke 4.15.0.1025.39
linux-image-lowlatency-hwe-16.04 4.15.0.42.63
linux-image-oem 4.15.0.42.63

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:
https://usn.ubuntu.com/usn/usn-3836-2
https://usn.ubuntu.com/usn/usn-3836-1
CVE-2018-18955, CVE-2018-6559

Package Information:
https://launchpad.net/ubuntu/+source/linux-gcp/4.15.0-1025.26~16.04.1
https://launchpad.net/ubuntu/+source/linux-hwe/4.15.0-42.45~16.04.1

Original Source

Url : http://www.ubuntu.com/usn/USN-3836-2

CWE : Common Weakness Enumeration

% Id Name
100 % CWE-200 Information Exposure

CPE : Common Platform Enumeration

TypeDescriptionCount
Os 3
Os 3174

Alert History

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0
1
2
Date Informations
2018-12-19 21:21:59
  • Multiple Updates
2018-12-07 00:21:24
  • Multiple Updates
2018-12-04 09:18:51
  • First insertion