Ubuntu 20.04 LTS : Linux kernel (OEM) vulnerabilities (USN-4915-1) - Nessus

High Plugin ID: 148689

This page contains detailed information about the Ubuntu 20.04 LTS : Linux kernel (OEM) vulnerabilities (USN-4915-1) 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: 148689
Name: Ubuntu 20.04 LTS : Linux kernel (OEM) vulnerabilities (USN-4915-1)
Filename: ubuntu_USN-4915-1.nasl
Vulnerability Published: 2021-04-15
This Plugin Published: 2021-04-16
Last Modification Time: 2022-01-21
Plugin Version: 1.6
Plugin Type: local
Plugin Family: Ubuntu Local Security Checks
Dependencies: linux_alt_patch_detect.nasl, ssh_get_info.nasl
Required KB Items [?]: Host/cpu, Host/Debian/dpkg-l, Host/Ubuntu, Host/Ubuntu/release

Vulnerability Information

Severity: High
Vulnerability Published: 2021-04-15
Patch Published: 2021-04-15
CVE [?]: CVE-2021-3492, CVE-2021-3493
CPE [?]: cpe:/o:canonical:ubuntu_linux:20.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.6.0-1054-oem, p-cpe:/a:canonical:ubuntu_linux:linux-image-oem-20.04
Exploited by Malware: True

Synopsis

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

Description

The remote Ubuntu 20.04 LTS host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-4915-1 advisory. 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 linux-image-5.6.0-1054-oem and / or linux-image-oem-20.04 packages.

Public Exploits

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

Here's the list of publicly known exploits and PoCs for verifying the Ubuntu 20.04 LTS : Linux kernel (OEM) vulnerabilities (USN-4915-1) vulnerability:

Metasploit: exploit/linux/local/cve_2021_3493_overlayfs
[2021 Ubuntu Overlayfs LPE]
GitHub: https://github.com/hac425xxx/heap-exploitation-in-real-world
[CVE-2021-3492]
GitHub: https://github.com/joydo/CVE-Writeups
[CVE-2021-3492]
GitHub: https://github.com/xairy/linux-kernel-exploitation
[CVE-2021-3492]
GitHub: https://github.com/Abdennour-py/CVE-2021-3493
[CVE-2021-3493]
GitHub: https://github.com/Al1ex/LinuxEelvation
[CVE-2021-3493]
GitHub: https://github.com/AmIAHuman/OverlayFS-CVE-2021-3493
[CVE-2021-3493]
GitHub: https://github.com/EdgeSecurityTeam/Vulnerability
[CVE-2021-3493]
GitHub: https://github.com/H0j3n/EzpzCheatSheet
[CVE-2021-3493]
GitHub: https://github.com/Ishan3011/CVE-2021-3493
[CVE-2021-3493]
GitHub: https://github.com/JamesGeee/CVE-2021-3493
[CVE-2021-3493: PoC for exploiting CVE-2021-3493]
GitHub: https://github.com/SexyBeast233/SecBooks
[CVE-2021-3493]
GitHub: https://github.com/ctrsploit/ctrsploit
[CVE-2021-3493]
GitHub: https://github.com/inspiringz/CVE-2021-3493
[CVE-2021-3493]
GitHub: https://github.com/oneoy/CVE-2021-3493
[CVE-2021-3493]
GitHub: https://github.com/puckiestyle/CVE-2021-3493
[CVE-2021-3493]
GitHub: https://github.com/xairy/linux-kernel-exploitation
[CVE-2021-3493]
GitHub: https://github.com/synacktiv/CVE-2021-3492
[CVE-2021-3492: PoC for CVE-2021-3492 used at Pwn2Own 2021]
GitHub: https://github.com/briskets/CVE-2021-3493
[CVE-2021-3493: Ubuntu OverlayFS Local Privesc]
GitHub: https://github.com/cerodah/overlayFS-CVE-2021-3493
[CVE-2021-3493: 2021 kernel vulnerability in Ubuntu]
GitHub: https://github.com/derek-turing/CVE-2021-3493
[CVE-2021-3493: CVE-2021-3493 Ubuntu漏洞]

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-2021-3493
CVSS V2 Vector: AV:L/AC:L/Au:N/C:C/I:C/A:C/E:H/RL:OF/RC:C

CVSS Base Score:	7.2 (High)
Impact Subscore:	10.0
Exploitability Subscore:	3.9
CVSS Temporal Score:	6.3 (Medium)
CVSS Environmental Score:	NA (None)
Modified Impact Subscore:	NA
Overall CVSS Score:	6.3 (Medium)

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

CVSS Base Score:	7.8 (High)
Impact Subscore:	5.9
Exploitability Subscore:	1.8
CVSS Temporal Score:	7.5 (High)
CVSS Environmental Score:	NA (None)
Modified Impact Subscore:	NA
Overall CVSS Score:	7.5 (High)

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Plugin Source

This is the ubuntu_USN-4915-1.nasl nessus plugin source code. Ubuntu Security Notice (C) 2021-2022 Canonical, Inc. / NASL script (C) 2021-2022 and is owned by Tenable, Inc. or an Affiliate thereof.

##
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Ubuntu Security Notice USN-4915-1. The text
# itself is copyright (C) Canonical, Inc. See
# <https://ubuntu.com/security/notices>. Ubuntu(R) is a registered
# trademark of Canonical, Inc.
##

include('compat.inc');

if (description)
{
  script_id(148689);
  script_version("1.6");
  script_set_attribute(attribute:"plugin_modification_date", value:"2022/01/21");

  script_cve_id("CVE-2021-3492", "CVE-2021-3493");
  script_xref(name:"USN", value:"4915-1");

  script_name(english:"Ubuntu 20.04 LTS : Linux kernel (OEM) vulnerabilities (USN-4915-1)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Ubuntu host is missing one or more security updates.");
  script_set_attribute(attribute:"description", value:
"The remote Ubuntu 20.04 LTS host has packages installed that are affected by multiple vulnerabilities as referenced in
the USN-4915-1 advisory. 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://ubuntu.com/security/notices/USN-4915-1");
  script_set_attribute(attribute:"solution", value:
"Update the affected linux-image-5.6.0-1054-oem and / or linux-image-oem-20.04 packages.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:N/C:C/I:C/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:H/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:L/PR:L/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-2021-3493");

  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:"metasploit_name", value:'2021 Ubuntu Overlayfs LPE');
  script_set_attribute(attribute:"exploit_framework_metasploit", value:"true");

  script_set_attribute(attribute:"vuln_publication_date", value:"2021/04/15");
  script_set_attribute(attribute:"patch_publication_date", value:"2021/04/15");
  script_set_attribute(attribute:"plugin_publication_date", value:"2021/04/16");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:20.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.6.0-1054-oem");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-oem-20.04");
  script_end_attributes();

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

  script_copyright(english:"Ubuntu Security Notice (C) 2021-2022 Canonical, Inc. / NASL script (C) 2021-2022 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/cpu", "Host/Ubuntu", "Host/Ubuntu/release", "Host/Debian/dpkg-l");

  exit(0);
}

include('audit.inc');
include('ubuntu.inc');
include('ksplice.inc');

if ( ! get_kb_item('Host/local_checks_enabled') ) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
release = get_kb_item('Host/Ubuntu/release');
if ( isnull(release) ) audit(AUDIT_OS_NOT, 'Ubuntu');
release = chomp(release);
if (! preg(pattern:"^(20\.04)$", string:release)) audit(AUDIT_OS_NOT, 'Ubuntu 20.04', 'Ubuntu ' + release);
if ( ! get_kb_item('Host/Debian/dpkg-l') ) audit(AUDIT_PACKAGE_LIST_MISSING);

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

if (get_one_kb_item('Host/ksplice/kernel-cves'))
{
  rm_kb_item(name:'Host/uptrack-uname-r');
  cve_list = make_list('CVE-2021-3492', 'CVE-2021-3493');
  if (ksplice_cves_check(cve_list))
  {
    audit(AUDIT_PATCH_INSTALLED, 'KSplice hotfix for USN-4915-1');
  }
  else
  {
    _ubuntu_report = ksplice_reporting_text();
  }
}

pkgs = [
    {'osver': '20.04', 'pkgname': 'linux-image-5.6.0-1054-oem', 'pkgver': '5.6.0-1054.58'},
    {'osver': '20.04', 'pkgname': 'linux-image-oem-20.04', 'pkgver': '5.6.0.1054.50'}
];

flag = 0;
foreach package_array ( pkgs ) {
  osver = NULL;
  pkgname = NULL;
  pkgver = NULL;
  if (!empty_or_null(package_array['osver'])) osver = package_array['osver'];
  if (!empty_or_null(package_array['pkgname'])) pkgname = package_array['pkgname'];
  if (!empty_or_null(package_array['pkgver'])) pkgver = package_array['pkgver'];
  if (osver && pkgname && pkgver) {
    if (ubuntu_check(osver:osver, pkgname:pkgname, pkgver:pkgver)) flag++;
  }
}

if (flag)
{
  security_report_v4(
    port       : 0,
    severity   : SECURITY_HOLE,
    extra      : ubuntu_report_get()
  );
  exit(0);
}
else
{
  tested = ubuntu_pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, 'linux-image-5.6.0-1054-oem / linux-image-oem-20.04');
}

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

Linux / Unix:
/opt/nessus/lib/nessus/plugins/ubuntu_USN-4915-1.nasl
Windows:
C:\ProgramData\Tenable\Nessus\nessus\plugins\ubuntu_USN-4915-1.nasl
Mac OS X:
/Library/Nessus/run/lib/nessus/plugins/ubuntu_USN-4915-1.nasl

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How to Run

Here is how to run the Ubuntu 20.04 LTS : Linux kernel (OEM) vulnerabilities (USN-4915-1) 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 Ubuntu Local Security Checks plugin family.
On the right side table select Ubuntu 20.04 LTS : Linux kernel (OEM) vulnerabilities (USN-4915-1) plugin ID 148689.
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 ubuntu_USN-4915-1.nasl -t <IP/HOST>

Run the plugin with audit trail message on the console:

/opt/nessus/bin/nasl -a ubuntu_USN-4915-1.nasl -t <IP/HOST>

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

/opt/nessus/bin/nasl -T - ubuntu_USN-4915-1.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 ubuntu_USN-4915-1.nasl -t <IP/HOST>

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References

USN | Ubuntu Security Notice:

4915-1

See also:

Similar and related Nessus plugins:

148691 - Ubuntu 16.04 LTS / 18.04 LTS : Linux kernel vulnerabilities (USN-4916-1)
148690 - Ubuntu 18.04 LTS / 20.04 LTS / 20.10 : Linux kernel vulnerabilities (USN-4917-1)

Version

This page has been produced using Nessus Professional 10.1.2 (#68) LINUX, Plugin set 202205072148.
Plugin file ubuntu_USN-4915-1.nasl version 1.6. For more plugins, visit the Nessus Plugin Library.

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Ubuntu 20.04 LTS : Linux kernel (OEM) vulnerabilities (USN-4915-1) - Nessus

Plugin Overview

Vulnerability Information

Synopsis

Description

Solution

Public Exploits

Risk Information

Plugin Source

How to Run

References

Version

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