Amazon Linux 2 : tigervnc (ALAS-2020-1552)

high Nessus Plugin ID 141997

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Synopsis

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

Description

The version of tested product installed on the remote host is prior to tested version. It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2-2020-1552 advisory.

- TigerVNC version prior to 1.10.1 is vulnerable to stack use-after-return, which occurs due to incorrect usage of stack memory in ZRLEDecoder. If decoding routine would throw an exception, ZRLEDecoder may try to access stack variable, which has been already freed during the process of stack unwinding. Exploitation of this vulnerability could potentially result into remote code execution. This attack appear to be exploitable via network connectivity. (CVE-2019-15691)

- TigerVNC version prior to 1.10.1 is vulnerable to heap buffer overflow. Vulnerability could be triggered from CopyRectDecoder due to incorrect value checks. Exploitation of this vulnerability could potentially result into remote code execution. This attack appear to be exploitable via network connectivity.
(CVE-2019-15692)

- TigerVNC version prior to 1.10.1 is vulnerable to heap buffer overflow, which occurs in TightDecoder::FilterGradient. Exploitation of this vulnerability could potentially result into remote code execution. This attack appear to be exploitable via network connectivity. (CVE-2019-15693)

- TigerVNC version prior to 1.10.1 is vulnerable to heap buffer overflow, which could be triggered from DecodeManager::decodeRect. Vulnerability occurs due to the signdness error in processing MemOutStream.
Exploitation of this vulnerability could potentially result into remote code execution. This attack appear to be exploitable via network connectivity. (CVE-2019-15694)

- TigerVNC version prior to 1.10.1 is vulnerable to stack buffer overflow, which could be triggered from CMsgReader::readSetCursor. This vulnerability occurs due to insufficient sanitization of PixelFormat.
Since remote attacker can choose offset from start of the buffer to start writing his values, exploitation of this vulnerability could potentially result into remote code execution. This attack appear to be exploitable via network connectivity. (CVE-2019-15695)

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 tigervnc' to update your system.

Plugin Details

Severity: High

ID: 141997

File Name: al2_ALAS-2020-1552.nasl

Version: 1.3

Type: local

Agent: unix

Family: Amazon Linux Local Security Checks

Published: 10/28/2020

Updated: 2/13/2024

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

Risk Information

VPR

Risk Factor: Medium

Score: 6.7

CVSS v2

Risk Factor: Medium

Base Score: 6.5

Temporal Score: 5.1

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

CVSS Score Source: CVE-2019-15695

CVSS v3

Risk Factor: High

Base Score: 7.2

Temporal Score: 6.5

Vector: CVSS:3.0/AV:N/AC:L/PR:H/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:tigervnc, p-cpe:/a:amazon:linux:tigervnc-debuginfo, p-cpe:/a:amazon:linux:tigervnc-icons, p-cpe:/a:amazon:linux:tigervnc-license, p-cpe:/a:amazon:linux:tigervnc-server, p-cpe:/a:amazon:linux:tigervnc-server-applet, p-cpe:/a:amazon:linux:tigervnc-server-minimal, p-cpe:/a:amazon:linux:tigervnc-server-module, cpe:/o:amazon:linux:2

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: 10/22/2020

Vulnerability Publication Date: 12/26/2019

Reference Information

CVE: CVE-2019-15691, CVE-2019-15692, CVE-2019-15693, CVE-2019-15694, CVE-2019-15695

ALAS: 2020-1552

Detections

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