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Ubuntu 18.04 LTS : Linux kernel vulnerabilities (USN-3836-1)

high Nessus Plugin ID 119339

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Synopsis

The remote Ubuntu host is missing one or more security updates.

Description

The remote Ubuntu 18.04 LTS host has a package installed that is affected by multiple vulnerabilities as referenced in the USN-3836-1 advisory.

 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)

Tenable has extracted the preceding description block directly from the Ubuntu security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

Solution

Update the affected kernel package.

See Also

https://ubuntu.com/security/notices/USN-3836-1

Plugin Details

Severity: High

ID: 119339

File Name: ubuntu_USN-3836-1.nasl

Version: 1.11

Type: local

Agent: unix

Published: 12/4/2018

Updated: 8/27/2024

Supported Sensors: Agentless Assessment, Continuous Assessment, Frictionless Assessment Agent, Frictionless Assessment AWS, Frictionless Assessment Azure, Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: High

Score: 8.4

CVSS v2

Risk Factor: Medium

Base Score: 4.4

Temporal Score: 3.6

Vector: CVSS2#AV:L/AC:M/Au:N/C:P/I:P/A:P

CVSS Score Source: CVE-2018-18955

CVSS v3

Risk Factor: High

Base Score: 7

Temporal Score: 6.5

Vector: CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

Temporal Vector: CVSS:3.0/E:F/RL:O/RC:C

Vulnerability Information

CPE: p-cpe:/a:canonical:ubuntu_linux:linux-image-4.15.0-42-generic-lpae, p-cpe:/a:canonical:ubuntu_linux:linux-image-4.15.0-42-snapdragon, p-cpe:/a:canonical:ubuntu_linux:linux-image-4.15.0-1025-gcp, p-cpe:/a:canonical:ubuntu_linux:linux-image-4.15.0-42-lowlatency, cpe:/o:canonical:ubuntu_linux:18.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:linux-image-4.15.0-1027-kvm, p-cpe:/a:canonical:ubuntu_linux:linux-image-4.15.0-1029-raspi2, p-cpe:/a:canonical:ubuntu_linux:linux-image-4.15.0-42-generic

Required KB Items: Host/cpu, Host/Ubuntu, Host/Ubuntu/release, Host/Debian/dpkg-l

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 12/3/2018

Vulnerability Publication Date: 10/26/2018

Exploitable With

Metasploit (Linux Nested User Namespace idmap Limit Local Privilege Escalation)

Reference Information

CVE: CVE-2018-18955, CVE-2018-6559

USN: 3836-1