Amazon Linux 2 : kernel (ALAS-2018-1038) (Spectre)

Medium Nessus Plugin ID 110455

Synopsis

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

Description

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)

By mmap()ing a FUSE-backed file onto a process's memory containing command line arguments (or environment strings), an attacker can cause utilities from psutils or procps (such as ps, w) or any other program which makes a read() call to the /proc/<pid>/cmdline (or /proc/<pid>/environ) files to block indefinitely (denial of service) or for some controlled time (as a synchronization primitive for other attacks).(CVE-2018-1120)

An industry-wide issue was found in the way many modern microprocessor designs have implemented speculative execution of instructions past bounds check. The flaw relies on the presence of a precisely-defined instruction sequence in the privileged code and the fact that memory writes occur to an address which depends on the untrusted value. Such writes 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 influence speculative execution and/or read privileged memory by conducting targeted cache side-channel attacks.(CVE-2018-3693)

Solution

Run 'yum update kernel' and reboot the instance to update your system.

See Also

https://alas.aws.amazon.com/AL2/ALAS-2018-1038.html

Plugin Details

Severity: Medium

ID: 110455

File Name: al2_ALAS-2018-1038.nasl

Version: 1.6

Type: local

Agent: unix

Published: 2018/06/12

Modified: 2018/09/19

Dependencies: 12634

Risk Information

Risk Factor: Medium

CVSSv2

Base Score: 4.9

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

CVSSv3

Base Score: 5.6

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

Vulnerability Information

CPE: p-cpe:/a:amazon:linux:kernel, p-cpe:/a:amazon:linux:kernel-debuginfo, p-cpe:/a:amazon:linux:kernel-debuginfo-common-x86_64, p-cpe:/a:amazon:linux:kernel-devel, p-cpe:/a:amazon:linux:kernel-headers, p-cpe:/a:amazon:linux:kernel-tools, p-cpe:/a:amazon:linux:kernel-tools-debuginfo, p-cpe:/a:amazon:linux:kernel-tools-devel, p-cpe:/a:amazon:linux:perf, p-cpe:/a:amazon:linux:perf-debuginfo, p-cpe:/a:amazon:linux:python-perf, p-cpe:/a:amazon:linux:python-perf-debuginfo, cpe:/o:amazon:linux:2

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

Patch Publication Date: 2018/09/15

Reference Information

CVE: CVE-2018-1120, CVE-2018-3639, CVE-2018-3693

ALAS: 2018-1038

IAVA: 2018-A-0174