Amazon Linux 2 : libX11 (ALAS-2021-1686)

critical Nessus Plugin ID 151795

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Synopsis

The remote Amazon Linux 2 host is missing a security update.

Description

The version of libX11 installed on the remote host is prior to 1.6.7-3. It is, therefore, affected by a vulnerability as referenced in the ALAS2-2021-1686 advisory.

- LookupCol.c in X.Org X through X11R7.7 and libX11 before 1.7.1 might allow remote attackers to execute arbitrary code. The libX11 XLookupColor request (intended for server-side color lookup) contains a flaw allowing a client to send color-name requests with a name longer than the maximum size allowed by the protocol (and also longer than the maximum packet size for normal-sized packets). The user-controlled data exceeding the maximum size is then interpreted by the server as additional X protocol requests and executed, e.g., to disable X server authorization completely. For example, if the victim encounters malicious terminal control sequences for color codes, then the attacker may be able to take full control of the running graphical session. (CVE-2021-31535)

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

Solution

Run 'yum update libX11' to update your system.

Plugin Details

Severity: Critical

ID: 151795

File Name: al2_ALAS-2021-1686.nasl

Version: 1.3

Type: local

Agent: unix

Family: Amazon Linux Local Security Checks

Published: 7/16/2021

Updated: 7/19/2021

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

Risk Information

VPR

Risk Factor: Medium

Score: 6.7

CVSS v2

Risk Factor: High

Base Score: 7.5

Temporal Score: 5.9

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

CVSS Score Source: CVE-2021-31535

CVSS v3

Risk Factor: Critical

Base Score: 9.8

Temporal Score: 8.8

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

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

Vulnerability Information

CPE: p-cpe:/a:amazon:linux:libx11-debuginfo, p-cpe:/a:amazon:linux:libx11, p-cpe:/a:amazon:linux:libx11-common, cpe:/o:amazon:linux:2, p-cpe:/a:amazon:linux:libx11-devel

Required KB Items: Host/local_checks_enabled, Host/AmazonLinux/release, Host/AmazonLinux/rpm-list

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 7/14/2021

Vulnerability Publication Date: 5/27/2021

Reference Information

CVE: CVE-2021-31535

ALAS: 2021-1686

Detections

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