Executive Summary

Summary
Title Linux kernel vulnerabilities
Informations
NameUSN-3836-1First vendor Publication2018-12-03
VendorUbuntuLast vendor Modification2018-12-03
Severity (Vendor) N/ARevisionN/A

Security-Database Scoring CVSS v2

Cvss vector : (AV:L/AC:L/Au:N/C:P/I:N/A:N)
Cvss Base Score2.1Attack RangeLocal
Cvss Impact Score2.9Attack ComplexityLow
Cvss Expoit Score3.9AuthenticationNone Required
Calculate full CVSS 2.0 Vectors scores

Detail

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

- Ubuntu 18.04 LTS

Summary:

Several security issues were fixed in the Linux kernel.

Software Description: - linux: Linux kernel - linux-gcp: Linux kernel for Google Cloud Platform (GCP) systems - linux-kvm: Linux kernel for cloud environments - linux-raspi2: Linux kernel for Raspberry Pi 2

Details:

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 18.04 LTS:
linux-image-4.15.0-1025-gcp 4.15.0-1025.26
linux-image-4.15.0-1027-kvm 4.15.0-1027.27
linux-image-4.15.0-1029-raspi2 4.15.0-1029.31
linux-image-4.15.0-42-generic 4.15.0-42.45
linux-image-4.15.0-42-generic-lpae 4.15.0-42.45
linux-image-4.15.0-42-lowlatency 4.15.0-42.45
linux-image-4.15.0-42-snapdragon 4.15.0-42.45
linux-image-gcp 4.15.0.1025.27
linux-image-generic 4.15.0.42.44
linux-image-generic-lpae 4.15.0.42.44
linux-image-gke 4.15.0.1025.27
linux-image-kvm 4.15.0.1027.27
linux-image-lowlatency 4.15.0.42.44
linux-image-raspi2 4.15.0.1029.27
linux-image-snapdragon 4.15.0.42.44

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-3836-1
CVE-2018-18955, CVE-2018-6559

Package Information:
https://launchpad.net/ubuntu/+source/linux/4.15.0-42.45
https://launchpad.net/ubuntu/+source/linux-gcp/4.15.0-1025.26
https://launchpad.net/ubuntu/+source/linux-kvm/4.15.0-1027.27
https://launchpad.net/ubuntu/+source/linux-raspi2/4.15.0-1029.31

Original Source

Url : http://www.ubuntu.com/usn/USN-3836-1

CWE : Common Weakness Enumeration

%idName
100 %CWE-200Information Exposure

CPE : Common Platform Enumeration

TypeDescriptionCount
Os3
Os1

Alert History

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0
1
2
DateInformations
2018-12-07 00:21:24
  • Multiple Updates
2018-12-04 17:21:54
  • Multiple Updates
2018-12-04 00:18:45
  • First insertion