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Ubuntu 16.10 / 17.04 : lightdm vulnerability (USN-3285-1)

medium Nessus Plugin ID 100156

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Synopsis

The remote Ubuntu host is missing a security-related patch.

Description

Tyler Hicks discovered that LightDM did not confine the user session for guest users. An attacker with physical access could use this issue to access files and other resources that they should not be able to access. In the default installation, this includes files in the home directories of other users on the system. This update fixes the issue by disabling the guest session. It may be re-enabled in a future update. Please see the bug referenced below for instructions on how to manually re-enable the guest session.

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 lightdm package.

See Also

https://usn.ubuntu.com/3285-1/

Plugin Details

Severity: Medium

ID: 100156

File Name: ubuntu_USN-3285-1.nasl

Version: 3.10

Type: local

Agent: unix

Published: 5/12/2017

Updated: 1/12/2023

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

Risk Information

VPR

Risk Factor: Low

Score: 3.6

CVSS v2

Risk Factor: Low

Base Score: 2.1

Temporal Score: 1.6

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

CVSS v3

Risk Factor: Medium

Base Score: 4.6

Temporal Score: 4

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

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

Vulnerability Information

CPE: cpe:/o:canonical:ubuntu_linux:17.04, p-cpe:/a:canonical:ubuntu_linux:lightdm, cpe:/o:canonical:ubuntu_linux:16.10

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

Exploit Ease: No known exploits are available

Patch Publication Date: 5/11/2017

Vulnerability Publication Date: 5/12/2017

Reference Information

CVE: CVE-2017-8900

USN: 3285-1