AlmaLinux 8 : kernel (ALSA-2021:4647) - Nessus

Critical Plugin ID: 157670

This page contains detailed information about the AlmaLinux 8 : kernel (ALSA-2021:4647) 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: 157670
Name: AlmaLinux 8 : kernel (ALSA-2021:4647)
Filename: alma_linux_ALSA-2021-4647.nasl
Vulnerability Published: 2021-09-27
This Plugin Published: 2022-02-09
Last Modification Time: 2022-02-14
Plugin Version: 1.4
Plugin Type: local
Plugin Family: Alma Linux Local Security Checks
Dependencies: linux_alt_patch_detect.nasl, ssh_get_info.nasl
Required KB Items [?]: Host/AlmaLinux/release, Host/AlmaLinux/rpm-list, Host/cpu, Host/local_checks_enabled

Vulnerability Information

Synopsis

The remote AlmaLinux host is missing one or more security updates.

Description

The remote AlmaLinux 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the ALSA-2021:4647 advisory.

- A flaw was found in the Linux kernel. A corrupted timer tree caused the task wakeup to be missing in the timerqueue_add function in lib/timerqueue.c. This flaw allows a local attacker with special user privileges to cause a denial of service, slowing and eventually stopping the system while running OSP. (CVE-2021-20317)

- An issue was discovered in net/tipc/crypto.c in the Linux kernel before 5.14.16. The Transparent Inter- Process Communication (TIPC) functionality allows remote attackers to exploit insufficient validation of user-supplied sizes for the MSG_CRYPTO message type. (CVE-2021-43267)

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

Solution

Update the affected packages.

Public Exploits

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

Here's the list of publicly known exploits and PoCs for verifying the AlmaLinux 8 : kernel (ALSA-2021:4647) vulnerability:

GitHub: https://github.com/0x0021h/expbox
[CVE-2021-43267]
GitHub: https://github.com/Al1ex/LinuxEelvation
[CVE-2021-43267]
GitHub: https://github.com/bcoles/kasld
[CVE-2021-43267]
GitHub: https://github.com/bsauce/kernel-exploit-factory
[CVE-2021-43267]
GitHub: https://github.com/bsauce/kernel-security-learning
[CVE-2021-43267]
GitHub: https://github.com/xairy/linux-kernel-exploitation
[CVE-2021-43267]
GitHub: https://github.com/ohnonoyesyes/CVE-2021-43267
[CVE-2021-43267: Local PoC exploit for CVE-2021-43267 (Linux TIPC)]
GitHub: https://github.com/DarkSprings/CVE-2021-43267-POC
[CVE-2021-43267: Trusty poc Provide it to legitimate people]

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-2021-43267
CVSS V2 Vector: AV:N/AC:L/Au:N/C:P/I:P/A:P/E:H/RL:OF/RC:C

CVSS Base Score:	7.5 (High)
Impact Subscore:	6.4
Exploitability Subscore:	10.0
CVSS Temporal Score:	6.5 (Medium)
CVSS Environmental Score:	NA (None)
Modified Impact Subscore:	NA
Overall CVSS Score:	6.5 (Medium)

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

CVSS Base Score:	9.8 (Critical)
Impact Subscore:	5.9
Exploitability Subscore:	3.9
CVSS Temporal Score:	9.4 (Critical)
CVSS Environmental Score:	NA (None)
Modified Impact Subscore:	NA
Overall CVSS Score:	9.4 (Critical)

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Plugin Source

#%NASL_MIN_LEVEL 70300
##
# (C) Tenable Network Security, Inc.
#
# The package checks in this plugin were extracted from
# AlmaLinux Security Advisory ALSA-2021:4647.
##

include('deprecated_nasl_level.inc');
include('compat.inc');

if (description)
{
  script_id(157670);
  script_version("1.4");
  script_set_attribute(attribute:"plugin_modification_date", value:"2022/02/14");

  script_cve_id("CVE-2021-20317", "CVE-2021-43267");
  script_xref(name:"ALSA", value:"2021:4647");

  script_name(english:"AlmaLinux 8 : kernel (ALSA-2021:4647)");

  script_set_attribute(attribute:"synopsis", value:
"The remote AlmaLinux host is missing one or more security updates.");
  script_set_attribute(attribute:"description", value:
"The remote AlmaLinux 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the
ALSA-2021:4647 advisory.

  - A flaw was found in the Linux kernel. A corrupted timer tree caused the task wakeup to be missing in the
    timerqueue_add function in lib/timerqueue.c. This flaw allows a local attacker with special user
    privileges to cause a denial of service, slowing and eventually stopping the system while running OSP.
    (CVE-2021-20317)

  - An issue was discovered in net/tipc/crypto.c in the Linux kernel before 5.14.16. The Transparent Inter-
    Process Communication (TIPC) functionality allows remote attackers to exploit insufficient validation of
    user-supplied sizes for the MSG_CRYPTO message type. (CVE-2021-43267)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version
number.");
  script_set_attribute(attribute:"see_also", value:"https://errata.almalinux.org/8/ALSA-2021-4647.html");
  script_set_attribute(attribute:"solution", value:
"Update the affected packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P");
  script_set_cvss_temporal_vector("CVSS2#E:H/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:H/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2021-43267");

  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");
  script_set_attribute(attribute:"exploited_by_malware", value:"true");

  script_set_attribute(attribute:"vuln_publication_date", value:"2021/09/27");
  script_set_attribute(attribute:"patch_publication_date", value:"2021/11/15");
  script_set_attribute(attribute:"plugin_publication_date", value:"2022/02/09");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:alma:linux:bpftool");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:alma:linux:kernel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:alma:linux:kernel-abi-stablelists");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:alma:linux:kernel-core");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:alma:linux:kernel-cross-headers");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:alma:linux:kernel-debug");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:alma:linux:kernel-debug-core");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:alma:linux:kernel-debug-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:alma:linux:kernel-debug-modules");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:alma:linux:kernel-debug-modules-extra");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:alma:linux:kernel-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:alma:linux:kernel-headers");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:alma:linux:kernel-modules");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:alma:linux:kernel-modules-extra");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:alma:linux:kernel-tools");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:alma:linux:kernel-tools-libs");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:alma:linux:kernel-tools-libs-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:alma:linux:perf");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:alma:linux:python3-perf");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:alma:linux:8");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Alma 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", "linux_alt_patch_detect.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/AlmaLinux/release", "Host/AlmaLinux/rpm-list", "Host/cpu");

  exit(0);
}


include('audit.inc');
include('global_settings.inc');
include('misc_func.inc');
include('rpm.inc');
include('ksplice.inc');

if (!get_kb_item('Host/local_checks_enabled')) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
var release = get_kb_item('Host/AlmaLinux/release');
if (isnull(release) || 'AlmaLinux' >!< release) audit(AUDIT_OS_NOT, 'AlmaLinux');
var os_ver = pregmatch(pattern: "AlmaLinux release ([0-9]+(\.[0-9]+)?)", string:release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, 'AlmaLinux');
var os_ver = os_ver[1];
if (! preg(pattern:"^8([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, 'AlmaLinux 8.x', 'AlmaLinux ' + os_ver);

if (!get_kb_item('Host/AlmaLinux/rpm-list')) audit(AUDIT_PACKAGE_LIST_MISSING);

var cpu = get_kb_item('Host/cpu');
if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
if ('x86_64' >!< cpu && cpu !~ "^i[3-6]86$" && 's390' >!< cpu && 'aarch64' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'AlmaLinux', cpu);

if (get_one_kb_item('Host/ksplice/kernel-cves'))
{
  rm_kb_item(name:'Host/uptrack-uname-r');
  var cve_list = make_list('CVE-2021-20317', 'CVE-2021-43267');
  if (ksplice_cves_check(cve_list))
  {
    audit(AUDIT_PATCH_INSTALLED, 'KSplice hotfix for ALSA-2021:4647');
  }
  else
  {
    __rpm_report = ksplice_reporting_text();
  }
}
var pkgs = [
    {'reference':'bpftool-4.18.0-348.2.1.el8_5', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-4.18.0-348.2.1.el8_5', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-abi-stablelists-4.18.0-348.2.1.el8_5', 'release':'8', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-core-4.18.0-348.2.1.el8_5', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-cross-headers-4.18.0-348.2.1.el8_5', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-debug-4.18.0-348.2.1.el8_5', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-debug-core-4.18.0-348.2.1.el8_5', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-debug-devel-4.18.0-348.2.1.el8_5', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-debug-modules-4.18.0-348.2.1.el8_5', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-debug-modules-extra-4.18.0-348.2.1.el8_5', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-devel-4.18.0-348.2.1.el8_5', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-headers-4.18.0-348.2.1.el8_5', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-modules-4.18.0-348.2.1.el8_5', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-modules-extra-4.18.0-348.2.1.el8_5', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-tools-4.18.0-348.2.1.el8_5', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-tools-libs-4.18.0-348.2.1.el8_5', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-tools-libs-devel-4.18.0-348.2.1.el8_5', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'perf-4.18.0-348.2.1.el8_5', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'python3-perf-4.18.0-348.2.1.el8_5', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE}
];

var flag = 0;
foreach var package_array ( pkgs ) {
  var reference = NULL;
  var release = NULL;
  var sp = NULL;
  var cpu = NULL;
  var el_string = NULL;
  var rpm_spec_vers_cmp = NULL;
  var epoch = NULL;
  var allowmaj = NULL;
  var exists_check = NULL;
  if (!empty_or_null(package_array['reference'])) reference = package_array['reference'];
  if (!empty_or_null(package_array['release'])) release = 'Alma-' + package_array['release'];
  if (!empty_or_null(package_array['sp'])) sp = package_array['sp'];
  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['epoch'])) epoch = package_array['epoch'];
  if (!empty_or_null(package_array['allowmaj'])) allowmaj = package_array['allowmaj'];
  if (!empty_or_null(package_array['exists_check'])) exists_check = package_array['exists_check'];
  if (reference && release && (!exists_check || rpm_exists(release:release, rpm:exists_check))) {
    if (rpm_check(release:release, sp:sp, cpu:cpu, reference:reference, epoch:epoch, el_string:el_string, rpm_spec_vers_cmp:rpm_spec_vers_cmp, allowmaj:allowmaj)) flag++;
  }
}

if (flag)
{
  security_report_v4(
      port       : 0,
      severity   : SECURITY_HOLE,
      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, 'bpftool / kernel / kernel-abi-stablelists / kernel-core / etc');
}

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

Linux / Unix:
/opt/nessus/lib/nessus/plugins/alma_linux_ALSA-2021-4647.nasl
Windows:
C:\ProgramData\Tenable\Nessus\nessus\plugins\alma_linux_ALSA-2021-4647.nasl
Mac OS X:
/Library/Nessus/run/lib/nessus/plugins/alma_linux_ALSA-2021-4647.nasl

Go back to menu.

How to Run

Here is how to run the AlmaLinux 8 : kernel (ALSA-2021:4647) 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 Alma Linux Local Security Checks plugin family.
On the right side table select AlmaLinux 8 : kernel (ALSA-2021:4647) plugin ID 157670.
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 alma_linux_ALSA-2021-4647.nasl -t <IP/HOST>

Run the plugin with audit trail message on the console:

/opt/nessus/bin/nasl -a alma_linux_ALSA-2021-4647.nasl -t <IP/HOST>

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

/opt/nessus/bin/nasl -T - alma_linux_ALSA-2021-4647.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 alma_linux_ALSA-2021-4647.nasl -t <IP/HOST>

Go back to menu.

References

See also:

Similar and related Nessus plugins:

160447 - Amazon Linux 2 : kernel (ALASKERNEL-5.10-2022-007)
155588 - CentOS 8 : kernel-rt (CESA-2021:4646)
155562 - CentOS 8 : kernel (CESA-2021:4647)
156163 - Debian DLA-2843-1 : linux - LTS security update
158761 - Debian DSA-5096-1 : linux - security update
155566 - Oracle Linux 8 : kernel (ELSA-2021-4647)
160190 - Oracle Linux 7 : Unbreakable Enterprise kernel (ELSA-2022-9313)
160189 - Oracle Linux 7 : Unbreakable Enterprise kernel-container (ELSA-2022-9314)
155322 - Photon OS 4.0: Linux PHSA-2021-4.0-0127
155361 - RHEL 8 : kpatch-patch (RHSA-2021:4644)
155364 - RHEL 8 : kpatch-patch (RHSA-2021:4645)
155368 - RHEL 8 : kernel-rt (RHSA-2021:4646)
155360 - RHEL 8 : kernel (RHSA-2021:4647)
155366 - RHEL 8 : kernel-rt (RHSA-2021:4648)
155367 - RHEL 8 : kernel (RHSA-2021:4650)
155654 - RHEL 8 : Red Hat Virtualization Host security and bug fix update [ovirt-4.4.9] 0-day (Important) (RHSA-2021:4750)
155746 - RHEL 8 : kernel (RHSA-2021:4871)
155745 - RHEL 8 : kernel-rt (RHSA-2021:4875)
157770 - Rocky Linux 8 : kernel-rt (RLSA-2021:4646)
157805 - Rocky Linux 8 : kernel (RLSA-2021:4647)
155750 - Ubuntu 20.04 LTS : Linux kernel (OEM) vulnerabilities (USN-5165-1)
156482 - Ubuntu 20.04 LTS : Linux kernel (OEM) vulnerabilities (USN-5207-1)
156486 - Ubuntu 20.04 LTS / 21.04 / 21.10 : Linux kernel vulnerabilities (USN-5208-1)
156613 - Ubuntu 20.04 LTS : Linux kernel (OEM) vulnerabilities (USN-5218-1)
159160 - Ubuntu 14.04 LTS / 16.04 LTS : Linux kernel vulnerabilities (USN-5343-1)

Version

This page has been produced using Nessus Professional 10.1.2 (#68) LINUX, Plugin set 202205072148.
Plugin file alma_linux_ALSA-2021-4647.nasl version 1.4. For more plugins, visit the Nessus Plugin Library.

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AlmaLinux 8 : kernel (ALSA-2021:4647) - Nessus

Plugin Overview

Vulnerability Information

Synopsis

Description

Solution

Public Exploits

Risk Information

Plugin Source

How to Run

References

Version

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