Amazon Linux 2 : kernel (ALASKERNEL-5.4-2022-018)

high Nessus Plugin ID 160441


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


The version of kernel installed on the remote host is prior to 5.4.80-40.140. It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2KERNEL-5.4-2022-018 advisory.

- A flaw was found in the Linux kernel. A use-after-free memory flaw was found in the perf subsystem allowing a local attacker with permission to monitor perf events to corrupt memory and possibly escalate privileges. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability. (CVE-2020-14351)

- A flaw was found in the Linux kernel. A use-after-free was found in the way the console subsystem was using ioctls KDGKBSENT and KDSKBSENT. A local user could use this flaw to get read memory access out of bounds. The highest threat from this vulnerability is to data confidentiality. (CVE-2020-25656)

- A flaw was found in Linux Kernel because access to the global variable fg_console is not properly synchronized leading to a use after free in con_font_op. (CVE-2020-25668)

- A flaw memory leak in the Linux kernel performance monitoring subsystem was found in the way if using PERF_EVENT_IOC_SET_FILTER. A local user could use this flaw to starve the resources causing denial of service. (CVE-2020-25704)

- An issue was discovered in the Linux kernel through 5.9.1, as used with Xen through 4.14.x. Guest OS users can cause a denial of service (host OS hang) via a high rate of events to dom0, aka CID-e99502f76271.

- An issue was discovered in the Linux kernel through 5.9.1, as used with Xen through 4.14.x.
drivers/xen/events/events_base.c allows event-channel removal during the event-handling loop (a race condition). This can cause a use-after-free or NULL pointer dereference, as demonstrated by a dom0 crash via events for an in-reconfiguration paravirtualized device, aka CID-073d0552ead5. (CVE-2020-27675)

- A slab-out-of-bounds read in fbcon in the Linux kernel before 5.9.7 could be used by local attackers to read privileged information or potentially crash the kernel, aka CID-3c4e0dff2095. This occurs because KD_FONT_OP_COPY in drivers/tty/vt/vt.c can be used for manipulations such as font height. (CVE-2020-28974)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.


Run 'yum update kernel' to update your system.

See Also

Plugin Details

Severity: High

ID: 160441

File Name: al2_ALASKERNEL-5_4-2022-018.nasl

Version: 1.4

Type: local

Agent: unix

Published: 5/2/2022

Updated: 6/7/2022

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

Risk Information


Risk Factor: Medium

Score: 6.7


Risk Factor: Medium

Base Score: 6.9

Temporal Score: 5.1

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

Temporal Vector: CVSS2#E:U/RL:OF/RC:C

CVSS Score Source: CVE-2020-25668


Risk Factor: High

Base Score: 7.8

Temporal Score: 6.8

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

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

CVSS Score Source: CVE-2020-14351

Vulnerability Information

CPE: cpe:2.3:o:amazon:linux:2:*:*:*:*:*:*:*, p-cpe:2.3:a:amazon:linux:kernel:*:*:*:*:*:*:*, p-cpe:2.3:a:amazon:linux:kernel-debuginfo:*:*:*:*:*:*:*, p-cpe:2.3:a:amazon:linux:kernel-debuginfo-common-x86_64:*:*:*:*:*:*:*, p-cpe:2.3:a:amazon:linux:kernel-devel:*:*:*:*:*:*:*, p-cpe:2.3:a:amazon:linux:kernel-headers:*:*:*:*:*:*:*, p-cpe:2.3:a:amazon:linux:kernel-tools:*:*:*:*:*:*:*, p-cpe:2.3:a:amazon:linux:kernel-tools-debuginfo:*:*:*:*:*:*:*, p-cpe:2.3:a:amazon:linux:kernel-tools-devel:*:*:*:*:*:*:*, p-cpe:2.3:a:amazon:linux:perf:*:*:*:*:*:*:*, p-cpe:2.3:a:amazon:linux:perf-debuginfo:*:*:*:*:*:*:*, p-cpe:2.3:a:amazon:linux:python-perf:*:*:*:*:*:*:*, p-cpe:2.3:a:amazon:linux:python-perf-debuginfo:*:*:*:*:*:*:*, p-cpe:2.3:a:amazon:linux:kernel-debuginfo-common-aarch64:*:*:*:*:*:*:*

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

Exploit Ease: No known exploits are available

Patch Publication Date: 1/20/2022

Vulnerability Publication Date: 10/22/2020

Reference Information

CVE: CVE-2020-27673, CVE-2020-27675, CVE-2020-14351, CVE-2020-25656, CVE-2020-25704, CVE-2020-25668, CVE-2020-28974