Amazon Linux AMI : qemu-kvm (ALAS-2018-1034) (Spectre)

high Nessus Plugin ID 110457


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


An out-of-bounds read access issue was found in the VGA display emulator built into the Quick emulator (QEMU). It could occur while reading VGA memory to update graphics display. A privileged user/process inside guest could use this flaw to crash the QEMU process on the host resulting in denial of service situation.(CVE-2017-13672)

A memory leakage issue was found in the I/O channels websockets implementation of the Quick Emulator (QEMU). It could occur while sending screen updates to a client, which is slow to read and process them further. A privileged guest user could use this flaw to cause a denial of service on the host and/or potentially crash the QEMU process instance on the host.(CVE-2017-15268)

A use-after-free issue was found in the Slirp networking implementation of the Quick emulator (QEMU). It occurs when a Socket referenced from multiple packets is freed while responding to a message. A user/process could use this flaw to crash the QEMU process on the host resulting in denial of service.(CVE-2017-13711 )

Quick Emulator (aka QEMU), when built with the Cirrus CLGD 54xx VGA Emulator support, allows local guest OS privileged users to cause a denial of service (out-of-bounds access and QEMU process crash) by leveraging incorrect region calculation when updating VGA display.(CVE-2018-7858)

VNC server implementation in Quick Emulator (QEMU) was found to be vulnerable to an unbounded memory allocation issue, as it did not throttle the framebuffer updates sent to its client. If the client did not consume these updates, VNC server allocates growing memory to hold onto this data. A malicious remote VNC client could use this flaw to cause DoS to the server host.(CVE-2017-15124)

An industry-wide issue was found in the way many modern microprocessor designs have implemented speculative execution of Load & Store instructions (a commonly used performance optimization). It relies on the presence of a precisely-defined instruction sequence in the privileged code as well as the fact that memory read from address to which a recent memory write has occurred may see an older value and subsequently cause an update into the microprocessor's data cache even for speculatively executed instructions that never actually commit (retire). As a result, an unprivileged attacker could use this flaw to read privileged memory by conducting targeted cache side-channel attacks.(CVE-2018-3639)

An out-of-bounds read access issue was found in the VGA emulator of QEMU. It could occur in vga_draw_text routine, while updating display area for a vnc client. A privileged user inside a guest could use this flaw to crash the QEMU process resulting in DoS.(CVE-2018-5683)


Run 'yum update qemu-kvm' to update your system.

See Also

Plugin Details

Severity: High

ID: 110457

File Name: ala_ALAS-2018-1034.nasl

Version: 1.2

Type: local

Agent: unix

Published: 6/12/2018

Updated: 4/5/2019

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

Risk Information


Risk Factor: Medium

Score: 6.7


Risk Factor: High

Base Score: 7.8

Temporal Score: 6.1

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


Risk Factor: High

Base Score: 7.5

Temporal Score: 6.7

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

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

Vulnerability Information

CPE: p-cpe:/a:amazon:linux:qemu-img, p-cpe:/a:amazon:linux:qemu-kvm, p-cpe:/a:amazon:linux:qemu-kvm-common, p-cpe:/a:amazon:linux:qemu-kvm-debuginfo, p-cpe:/a:amazon:linux:qemu-kvm-tools, cpe:/o:amazon:linux

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: 6/8/2018

Reference Information

CVE: CVE-2017-13672, CVE-2017-13711, CVE-2017-15124, CVE-2017-15268, CVE-2018-3639, CVE-2018-5683, CVE-2018-7858

ALAS: 2018-1034