Amazon Linux 2 : kernel (ALAS-2018-994)

High Nessus Plugin ID 109177

Synopsis

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

Description

Race condition in the store_int_with_restart() function in cpu/mcheck/mce.c :

A race condition in the store_int_with_restart() function in arch/x86/kernel/cpu/mcheck/mce.c in the Linux kernel allows local users to cause a denial of service (panic) by leveraging root access to write to the check_interval file in a /sys/devices/system/machinecheck/machinecheck<cpu number> directory.
(CVE-2018-7995)

Out-of-bounds write via userland offsets in ebt_entry struct in netfilter/ebtables.c :

A flaw was found in the Linux kernel's implementation of 32-bit syscall interface for bridging. This allowed a privileged user to arbitrarily write to a limited range of kernel memory. (CVE-2018-1068)

A flaw was found in the Linux kernel's skcipher component, which affects the skcipher_recvmsg function. Attackers using a specific input can lead to a privilege escalation.(CVE-2017-13215)

The do_get_mempolicy() function in mm/mempolicy.c in the Linux kernel allows local users to hit a use-after-free bug via crafted system calls and thus cause a denial of service (DoS) or possibly have unspecified other impact. Due to the nature of the flaw, privilege escalation cannot be fully ruled out.(CVE-2018-10675)

A flaw was found in Linux kernel's KVM virtualization subsystem. The VMX code does not restore the GDT.LIMIT to the previous host value, but instead sets it to 64KB. With a corrupted GDT limit a host's userspace code has an ability to place malicious entries in the GDT, particularly to the per-cpu variables. An attacker can use this to escalate their privileges.(CVE-2018-10901)

Solution

Run 'yum update kernel' to update the kernel and reboot your instance to start the new kernel

See Also

https://alas.aws.amazon.com/AL2/ALAS-2018-994.html

Plugin Details

Severity: High

ID: 109177

File Name: al2_ALAS-2018-994.nasl

Version: 1.3

Type: local

Agent: unix

Published: 2018/04/20

Updated: 2018/09/19

Dependencies: 12634

Risk Information

Risk Factor: High

CVSS v2.0

Base Score: 7.2

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

CVSS v3.0

Base Score: 7.8

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

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-2017-13215, CVE-2018-10675, CVE-2018-1068, CVE-2018-10901, CVE-2018-7995

ALAS: 2018-994