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Ubuntu 18.04 LTS : Linux kernel (AWS) vulnerabilities (USN-3833-1)

high Nessus Plugin ID 119303

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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-3833-1 advisory.

 - In the Linux kernel 4.15.x through 4.19.x before 4.19.2, map_write() in kernel/user_namespace.c allows privilege escalation because it mishandles nested user namespaces with more than 5 UID or GID ranges. A user who has CAP_SYS_ADMIN in an affected user namespace can bypass access controls on resources outside the namespace, as demonstrated by reading /etc/shadow. This occurs because an ID transformation takes place properly for the namespaced-to-kernel direction but not for the kernel-to-namespaced direction.
 (CVE-2018-18955)

 - The Linux kernel, as used in Ubuntu 18.04 LTS and Ubuntu 18.10, allows local users to obtain names of files in which they would not normally be able to access via an overlayfs mount inside of a user namespace. (CVE-2018-6559)

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-3833-1

Plugin Details

Severity: High

ID: 119303

File Name: ubuntu_USN-3833-1.nasl

Version: 1.11

Type: local

Agent: unix

Published: 11/30/2018

Updated: 1/9/2024

Supported Sensors: Agentless 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-4.15.0-1029-aws, 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: 11/30/2018

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: 3833-1