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

High Plugin ID: 160441

This page contains detailed information about the Amazon Linux 2 : kernel (ALASKERNEL-5.4-2022-018) Nessus plugin including available exploits and PoCs found on GitHub, in Metasploit or Exploit-DB for verifying of this vulnerability.

Table Of Contents

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Plugin Overview
Vulnerability Information

Synopsis
Description
Solution

Public Exploits
Risk Information
Plugin Source
How to Run
References
Version

Plugin Overview

ID: 160441
Name: Amazon Linux 2 : kernel (ALASKERNEL-5.4-2022-018)
Filename: al2_ALASKERNEL-5_4-2022-018.nasl
Vulnerability Published: 2020-10-22
This Plugin Published: 2022-05-02
Last Modification Time: 2022-05-02
Plugin Version: 1.2
Plugin Type: local
Plugin Family: Amazon Linux Local Security Checks
Dependencies: ssh_get_info.nasl
Required KB Items [?]: Host/AmazonLinux/release, Host/AmazonLinux/rpm-list, Host/local_checks_enabled

Vulnerability Information

Synopsis

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

Description

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. (CVE-2020-27673)

- 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.

Solution

Run 'yum update kernel' to update your system.

Public Exploits

Target Network Port(s): N/A
Target Asset(s): N/A
Exploit Available: True (GitHub)
Exploit Ease: Exploits (PoCs) are available

Here's the list of publicly known exploits and PoCs for verifying the Amazon Linux 2 : kernel (ALASKERNEL-5.4-2022-018) vulnerability:

GitHub: https://github.com/JaskaranNarula/Host_Errata_Info
[CVE-2020-25704]
GitHub: https://github.com/ZIllR0/Routers
[CVE-2020-28974]

Before running any exploit against any system, make sure you are authorized by the owner of the target system(s) to perform such activity. In any other case, this would be considered as an illegal activity.

WARNING: Beware of using unverified exploits from sources such as GitHub or Exploit-DB. These exploits and PoCs could contain malware. For more information, see how to use exploits safely.

Risk Information

CVSS Score Source [?]: CVE-2020-25668
CVSS V2 Vector: AV:L/AC:M/Au:N/C:C/I:C/A:C/E:U/RL:OF/RC:C

CVSS Base Score:	6.9 (Medium)
Impact Subscore:	10.0
Exploitability Subscore:	3.4
CVSS Temporal Score:	5.1 (Medium)
CVSS Environmental Score:	NA (None)
Modified Impact Subscore:	NA
Overall CVSS Score:	5.1 (Medium)

CVSS V3 Vector: CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C

CVSS Base Score:	7.0 (High)
Impact Subscore:	5.9
Exploitability Subscore:	1.0
CVSS Temporal Score:	6.1 (Medium)
CVSS Environmental Score:	NA (None)
Modified Impact Subscore:	NA
Overall CVSS Score:	6.1 (Medium)

Go back to menu.

Plugin Source

##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Amazon Linux 2 Security Advisory ALASKERNEL-5.4-2022-018.
##

include('compat.inc');

if (description)
{
  script_id(160441);
  script_version("1.2");
  script_set_attribute(attribute:"plugin_modification_date", value:"2022/05/02");

  script_cve_id(
    "CVE-2020-14351",
    "CVE-2020-25656",
    "CVE-2020-25668",
    "CVE-2020-25704",
    "CVE-2020-27673",
    "CVE-2020-27675",
    "CVE-2020-28974"
  );

  script_name(english:"Amazon Linux 2 : kernel (ALASKERNEL-5.4-2022-018)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Amazon Linux 2 host is missing a security update.");
  script_set_attribute(attribute:"description", value:
"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.
    (CVE-2020-27673)

  - 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.");
  script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/AL2/ALASKERNEL-5.4-2022-018.html");
  script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/cve/html/CVE-2020-14351.html");
  script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/cve/html/CVE-2020-25656.html");
  script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/cve/html/CVE-2020-25668.html");
  script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/cve/html/CVE-2020-25704.html");
  script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/cve/html/CVE-2020-27673.html");
  script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/cve/html/CVE-2020-27675.html");
  script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/cve/html/CVE-2020-28974.html");
  script_set_attribute(attribute:"solution", value:
"Run 'yum update kernel' to update your system.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:M/Au:N/C:C/I:C/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2020-25668");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"false");

  script_set_attribute(attribute:"vuln_publication_date", value:"2020/10/22");
  script_set_attribute(attribute:"patch_publication_date", value:"2022/01/20");
  script_set_attribute(attribute:"plugin_publication_date", value:"2022/05/02");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:kernel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:kernel-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:kernel-debuginfo-common-aarch64");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:kernel-debuginfo-common-x86_64");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:kernel-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:kernel-headers");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:kernel-tools");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:kernel-tools-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:kernel-tools-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:perf");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:perf-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:python-perf");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:python-perf-debuginfo");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:amazon:linux:2");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Amazon Linux Local Security Checks");

  script_copyright(english:"This script is Copyright (C) 2022 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/AmazonLinux/release", "Host/AmazonLinux/rpm-list");

  exit(0);
}

include("rpm.inc");
include("hotfixes.inc");

if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);

var release = get_kb_item("Host/AmazonLinux/release");
if (isnull(release) || !strlen(release)) audit(AUDIT_OS_NOT, "Amazon Linux");
var os_ver = pregmatch(pattern: "^AL(A|\d)", string:release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, "Amazon Linux");
var os_ver = os_ver[1];
if (os_ver != "2")
{
  if (os_ver == 'A') os_ver = 'AMI';
  audit(AUDIT_OS_NOT, "Amazon Linux 2", "Amazon Linux " + os_ver);
}

if (!get_kb_item("Host/AmazonLinux/rpm-list")) audit(AUDIT_PACKAGE_LIST_MISSING);

if (get_one_kb_item("Host/kpatch/kernel-cves"))
{
  set_hotfix_type("kpatch");
  var cve_list = make_list("CVE-2020-14351", "CVE-2020-25656", "CVE-2020-25668", "CVE-2020-25704", "CVE-2020-27673", "CVE-2020-27675", "CVE-2020-28974");
  if (hotfix_cves_check(cve_list))
  {
    audit(AUDIT_PATCH_INSTALLED, "kpatch hotfix for ALASKERNEL-5.4-2022-018");
  }
  else
  {
    __rpm_report = hotfix_reporting_text();
  }
}
var pkgs = [
    {'reference':'kernel-5.4.80-40.140.amzn2', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-5.4.80-40.140.amzn2', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-debuginfo-5.4.80-40.140.amzn2', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-debuginfo-5.4.80-40.140.amzn2', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-debuginfo-common-aarch64-5.4.80-40.140.amzn2', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-debuginfo-common-x86_64-5.4.80-40.140.amzn2', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-devel-5.4.80-40.140.amzn2', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-devel-5.4.80-40.140.amzn2', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-headers-5.4.80-40.140.amzn2', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-headers-5.4.80-40.140.amzn2', 'cpu':'i686', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-headers-5.4.80-40.140.amzn2', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-tools-5.4.80-40.140.amzn2', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-tools-5.4.80-40.140.amzn2', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-tools-debuginfo-5.4.80-40.140.amzn2', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-tools-debuginfo-5.4.80-40.140.amzn2', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-tools-devel-5.4.80-40.140.amzn2', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-tools-devel-5.4.80-40.140.amzn2', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'perf-5.4.80-40.140.amzn2', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'perf-5.4.80-40.140.amzn2', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'perf-debuginfo-5.4.80-40.140.amzn2', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'perf-debuginfo-5.4.80-40.140.amzn2', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'python-perf-5.4.80-40.140.amzn2', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'python-perf-5.4.80-40.140.amzn2', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'python-perf-debuginfo-5.4.80-40.140.amzn2', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'python-perf-debuginfo-5.4.80-40.140.amzn2', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE}
];

var flag = 0;
foreach package_array ( pkgs ) {
  var reference = NULL;
  var release = NULL;
  var cpu = NULL;
  var el_string = NULL;
  var rpm_spec_vers_cmp = NULL;
  var allowmaj = NULL;
  if (!empty_or_null(package_array['reference'])) reference = package_array['reference'];
  if (!empty_or_null(package_array['release'])) release = package_array['release'];
  if (!empty_or_null(package_array['cpu'])) cpu = package_array['cpu'];
  if (!empty_or_null(package_array['el_string'])) el_string = package_array['el_string'];
  if (!empty_or_null(package_array['rpm_spec_vers_cmp'])) rpm_spec_vers_cmp = package_array['rpm_spec_vers_cmp'];
  if (!empty_or_null(package_array['allowmaj'])) allowmaj = package_array['allowmaj'];
  if (reference && release) {
    if (rpm_check(release:release, cpu:cpu, reference:reference, el_string:el_string, rpm_spec_vers_cmp:rpm_spec_vers_cmp, allowmaj:allowmaj)) flag++;
  }
}

if (flag)
{
  security_report_v4(
      port       : 0,
      severity   : SECURITY_WARNING,
      extra      : rpm_report_get()
  );
  exit(0);
}
else
{
  var tested = pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, "kernel / kernel-debuginfo / kernel-debuginfo-common-x86_64 / etc");
}

The latest version of this script can be found in these locations depending on your platform:

Linux / Unix:
/opt/nessus/lib/nessus/plugins/al2_ALASKERNEL-5_4-2022-018.nasl
Windows:
C:\ProgramData\Tenable\Nessus\nessus\plugins\al2_ALASKERNEL-5_4-2022-018.nasl
Mac OS X:
/Library/Nessus/run/lib/nessus/plugins/al2_ALASKERNEL-5_4-2022-018.nasl

Go back to menu.

How to Run

Here is how to run the Amazon Linux 2 : kernel (ALASKERNEL-5.4-2022-018) as a standalone plugin via the Nessus web user interface (https://localhost:8834/):

Click to start a New Scan.
Select Advanced Scan.
Navigate to the Plugins tab.
On the top right corner click to Disable All plugins.
On the left side table select Amazon Linux Local Security Checks plugin family.
On the right side table select Amazon Linux 2 : kernel (ALASKERNEL-5.4-2022-018) plugin ID 160441.
Specify the target on the Settings tab and click to Save the scan.
Run the scan.

Here are a few examples of how to run the plugin in the command line. Note that the examples below demonstrate the usage on the Linux / Unix platform.

Basic usage:

/opt/nessus/bin/nasl al2_ALASKERNEL-5_4-2022-018.nasl -t <IP/HOST>

Run the plugin with audit trail message on the console:

/opt/nessus/bin/nasl -a al2_ALASKERNEL-5_4-2022-018.nasl -t <IP/HOST>

Run the plugin with trace script execution written to the console (useful for debugging):

/opt/nessus/bin/nasl -T - al2_ALASKERNEL-5_4-2022-018.nasl -t <IP/HOST>

Run the plugin with using a state file for the target and updating it (useful for running multiple plugins on the target):

/opt/nessus/bin/nasl -K /tmp/state al2_ALASKERNEL-5_4-2022-018.nasl -t <IP/HOST>

Go back to menu.

References

See also:

Similar and related Nessus plugins:

151229 - EulerOS Virtualization 3.0.6.6 : kernel (EulerOS-SA-2021-2040)
151307 - EulerOS Virtualization for ARM 64 3.0.2.0 : kernel (EulerOS-SA-2021-2075)
151419 - EulerOS Virtualization 3.0.2.2 : kernel (EulerOS-SA-2021-2140)
151730 - openSUSE 15 Security Update : kernel (openSUSE-SU-2021:1975-1)
151756 - openSUSE 15 Security Update : kernel (openSUSE-SU-2021:1977-1)
151856 - RHEL 8 : kernel-rt (RHSA-2021:2719)
151857 - RHEL 8 : kernel (RHSA-2021:2718)
154517 - NewStart CGSL CORE 5.04 / MAIN 5.04 : kernel Multiple Vulnerabilities (NS-SA-2021-0104)
154593 - NewStart CGSL MAIN 6.02 : kernel Multiple Vulnerabilities (NS-SA-2021-0126)
156632 - RHEL 7 : kernel-rt (RHSA-2022:0065)
156664 - Oracle Linux 7 : kernel (ELSA-2022-0063)
156726 - RHEL 7 : kernel (RHSA-2022:0063)
156757 - Scientific Linux Security Update : kernel on SL7.x x86_64 (2022:0063)
156820 - CentOS 7 : kernel (CESA-2022:0063)
157506 - AlmaLinux 8 : kernel (ALSA-2021:0558)
157595 - AlmaLinux 8 : kernel (ALSA-2021:1578)
159379 - F5 Networks BIG-IP : Linux kernel vulnerability (K44994972)

Version

This page has been produced using Nessus Professional 10.1.2 (#68) LINUX, Plugin set 202205072148.
Plugin file al2_ALASKERNEL-5_4-2022-018.nasl version 1.2. For more plugins, visit the Nessus Plugin Library.

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

Plugin Overview

Vulnerability Information

Synopsis

Description

Solution

Public Exploits

Risk Information

Plugin Source

How to Run

References

Version

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