Ubuntu 18.04 LTS : linux, linux-gcp, linux-kvm, linux-raspi2 vulnerabilities (USN-3836-1)

Medium Nessus Plugin ID 119339

Synopsis

The remote Ubuntu host is missing one or more security-related patches.

Description

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).

Note that Tenable Network Security has extracted the preceding description block directly from the Ubuntu security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

Solution

Update the affected packages.

See Also

https://usn.ubuntu.com/3836-1/

Plugin Details

Severity: Medium

ID: 119339

File Name: ubuntu_USN-3836-1.nasl

Version: 1.5

Type: local

Agent: unix

Published: 2018/12/04

Updated: 2019/04/05

Dependencies: 12634, 122878

Risk Information

Risk Factor: Medium

CVSS v2.0

Base Score: 4.4

Temporal Score: 3.6

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

Temporal Vector: CVSS2#E:F/RL:OF/RC:C

CVSS v3.0

Base Score: 7

Temporal Score: 6.4

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-gcp, p-cpe:/a:canonical:ubuntu_linux:linux-image-4.15-generic, p-cpe:/a:canonical:ubuntu_linux:linux-image-4.15-generic-lpae, p-cpe:/a:canonical:ubuntu_linux:linux-image-4.15-kvm, p-cpe:/a:canonical:ubuntu_linux:linux-image-4.15-lowlatency, p-cpe:/a:canonical:ubuntu_linux:linux-image-4.15-raspi2, p-cpe:/a:canonical:ubuntu_linux:linux-image-4.15-snapdragon, p-cpe:/a:canonical:ubuntu_linux:linux-image-gcp, p-cpe:/a:canonical:ubuntu_linux:linux-image-generic, p-cpe:/a:canonical:ubuntu_linux:linux-image-generic-lpae, p-cpe:/a:canonical:ubuntu_linux:linux-image-gke, p-cpe:/a:canonical:ubuntu_linux:linux-image-kvm, p-cpe:/a:canonical:ubuntu_linux:linux-image-lowlatency, p-cpe:/a:canonical:ubuntu_linux:linux-image-raspi2, p-cpe:/a:canonical:ubuntu_linux:linux-image-snapdragon, cpe:/o:canonical:ubuntu_linux:18.04:-:lts

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: 2018/12/03

Vulnerability Publication Date: 2018/10/26

Exploitable With

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

Reference Information

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

USN: 3836-1