Amazon Linux AMI : tigervnc (ALAS-2017-879)

critical Nessus Plugin ID 102867

Synopsis

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

Description

Buffer overflow in ModifiablePixelBuffer::fillRect

A buffer overflow flaw, leading to memory corruption, was found in TigerVNC viewer. A remote malicious VNC server could use this flaw to crash the client vncviewer process resulting in denial of service.
(CVE-2017-5581)

VNC server can crash when TLS handshake terminates early :

A denial of service flaw was found in the TigerVNC's Xvnc server. A remote unauthenticated attacker could use this flaw to make Xvnc crash by terminating the TLS handshake process early. (CVE-2016-10207)

SSecurityVeNCrypt memory leak :

A memory leak flaw was found in the way TigerVNC handled termination of VeNCrypt connections. A remote unauthenticated attacker could repeatedly send connection requests to the Xvnc server, causing it to consume large amounts of memory resources over time, and ultimately leading to a denial of service due to memory exhaustion.
(CVE-2017-7392)

Double free via crafted fences :

A double free flaw was found in the way TigerVNC handled ClientFence messages. A remote, authenticated attacker could use this flaw to make Xvnc crash by sending specially crafted ClientFence messages, resulting in denial of service. (CVE-2017-7393)

Server crash via long usernames :

A missing input sanitization flaw was found in the way TigerVNC handled credentials. A remote unauthenticated attacker could use this flaw to make Xvnc crash by sending specially crafted usernames, resulting in denial of service. (CVE-2017-7394)

Integer overflow in SMsgReader::readClientCutText :

An integer overflow flaw was found in the way TigerVNC handled ClientCutText messages. A remote, authenticated attacker could use this flaw to make Xvnc crash by sending specially crafted ClientCutText messages, resulting in denial of service.
(CVE-2017-7395)

SecurityServer and ClientServer memory leaks :

A memory leak flaw was found in the way TigerVNC handled client connections. A remote unauthenticated attacker could repeatedly send connection requests to the Xvnc server, causing it to consume large amounts of memory resources over time, and ultimately leading to a denial of service due to memory exhaustion. (CVE-2017-7396)

Solution

Run 'yum update tigervnc' to update your system.

See Also

https://alas.aws.amazon.com/ALAS-2017-879.html

Plugin Details

Severity: Critical

ID: 102867

File Name: ala_ALAS-2017-879.nasl

Version: 3.2

Type: local

Agent: unix

Published: 9/1/2017

Updated: 4/18/2018

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

Risk Information

VPR

Risk Factor: Medium

Score: 5.9

CVSS v2

Risk Factor: Medium

Base Score: 6.8

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

CVSS v3

Risk Factor: Critical

Base Score: 9.8

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

Vulnerability Information

CPE: p-cpe:/a:amazon:linux:tigervnc, p-cpe:/a:amazon:linux:tigervnc-debuginfo, p-cpe:/a:amazon:linux:tigervnc-server, p-cpe:/a:amazon:linux:tigervnc-server-module, cpe:/o:amazon:linux

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

Patch Publication Date: 8/31/2017

Reference Information

CVE: CVE-2016-10207, CVE-2017-5581, CVE-2017-7392, CVE-2017-7393, CVE-2017-7394, CVE-2017-7395, CVE-2017-7396

ALAS: 2017-879