Ubuntu 16.04 LTS / 18.04 LTS / 20.04 LTS / 21.04 / 21.10 : Ruby vulnerabilities (USN-5235-1) - Nessus

Critical Plugin ID: 156802

This page contains detailed information about the Ubuntu 16.04 LTS / 18.04 LTS / 20.04 LTS / 21.04 / 21.10 : Ruby vulnerabilities (USN-5235-1) 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: 156802
Name: Ubuntu 16.04 LTS / 18.04 LTS / 20.04 LTS / 21.04 / 21.10 : Ruby vulnerabilities (USN-5235-1)
Filename: ubuntu_USN-5235-1.nasl
Vulnerability Published: 2021-12-28
This Plugin Published: 2022-01-18
Last Modification Time: 2022-02-15
Plugin Version: 1.4
Plugin Type: local
Plugin Family: Ubuntu Local Security Checks
Dependencies: ssh_get_info.nasl
Required KB Items [?]: Host/cpu, Host/Debian/dpkg-l, Host/Ubuntu, Host/Ubuntu/release

Vulnerability Information

Synopsis

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

Description

The remote Ubuntu 16.04 LTS / 18.04 LTS / 20.04 LTS / 21.04 / 21.10 host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-5235-1 advisory.

- CGI::Cookie.parse in Ruby through 2.6.8 mishandles security prefixes in cookie names. This also affects the CGI gem through 0.3.0 for Ruby. (CVE-2021-41819)

- CGI.escape_html in Ruby before 2.7.5 and 3.x before 3.0.3 has an integer overflow and resultant buffer overflow via a long string on platforms (such as Windows) where size_t and long have different numbers of bytes. This also affects the CGI gem before 0.3.1 for Ruby. (CVE-2021-41816)

- Date.parse in the date gem through 3.2.0 for Ruby allows ReDoS (regular expression Denial of Service) via a long string. The fixed versions are 3.2.1, 3.1.2, 3.0.2, and 2.0.1. (CVE-2021-41817)

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 (PoCs) are available

Here's the list of publicly known exploits and PoCs for verifying the Ubuntu 16.04 LTS / 18.04 LTS / 20.04 LTS / 21.04 / 21.10 : Ruby vulnerabilities (USN-5235-1) vulnerability:

GitHub: https://github.com/lifeparticle/Ruby-Cheatsheet
[CVE-2021-41816]
GitHub: https://github.com/lifeparticle/Ruby-Cheatsheet
[CVE-2021-41817]
GitHub: https://github.com/lifeparticle/Ruby-Cheatsheet
[CVE-2021-41819]

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-2021-41816
CVSS V2 Vector: AV:N/AC:L/Au:N/C:P/I:P/A:P/E:U/RL:OF/RC:C

CVSS Base Score:	7.5 (High)
Impact Subscore:	6.4
Exploitability Subscore:	10.0
CVSS Temporal Score:	5.5 (Medium)
CVSS Environmental Score:	NA (None)
Modified Impact Subscore:	NA
Overall CVSS Score:	5.5 (Medium)

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

CVSS Base Score:	9.8 (Critical)
Impact Subscore:	5.9
Exploitability Subscore:	3.9
CVSS Temporal Score:	8.5 (High)
CVSS Environmental Score:	NA (None)
Modified Impact Subscore:	NA
Overall CVSS Score:	8.5 (High)

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Plugin Source

#%NASL_MIN_LEVEL 70300
##
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Ubuntu Security Notice USN-5235-1. The text
# itself is copyright (C) Canonical, Inc. See
# <https://ubuntu.com/security/notices>. Ubuntu(R) is a registered
# trademark of Canonical, Inc.
##

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

if (description)
{
  script_id(156802);
  script_version("1.4");
  script_set_attribute(attribute:"plugin_modification_date", value:"2022/02/15");

  script_cve_id("CVE-2021-41816", "CVE-2021-41817", "CVE-2021-41819");
  script_xref(name:"USN", value:"5235-1");

  script_name(english:"Ubuntu 16.04 LTS / 18.04 LTS / 20.04 LTS / 21.04 / 21.10 : Ruby vulnerabilities (USN-5235-1)");

  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 16.04 LTS / 18.04 LTS / 20.04 LTS / 21.04 / 21.10 host has packages installed that are affected by
multiple vulnerabilities as referenced in the USN-5235-1 advisory.

  - CGI::Cookie.parse in Ruby through 2.6.8 mishandles security prefixes in cookie names. This also affects
    the CGI gem through 0.3.0 for Ruby. (CVE-2021-41819)

  - CGI.escape_html in Ruby before 2.7.5 and 3.x before 3.0.3 has an integer overflow and resultant buffer
    overflow via a long string on platforms (such as Windows) where size_t and long have different numbers of
    bytes. This also affects the CGI gem before 0.3.1 for Ruby. (CVE-2021-41816)

  - Date.parse in the date gem through 3.2.0 for Ruby allows ReDoS (regular expression Denial of Service) via
    a long string. The fixed versions are 3.2.1, 3.1.2, 3.0.2, and 2.0.1. (CVE-2021-41817)

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-5235-1");
  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:U/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:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2021-41816");

  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:"2021/12/28");
  script_set_attribute(attribute:"patch_publication_date", value:"2022/01/18");
  script_set_attribute(attribute:"plugin_publication_date", value:"2022/01/18");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:16.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:18.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:20.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:21.04");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:21.10");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libruby2.3");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libruby2.5");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libruby2.7");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:ruby2.3");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:ruby2.3-dev");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:ruby2.3-tcltk");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:ruby2.5");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:ruby2.5-dev");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:ruby2.7");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:ruby2.7-dev");
  script_end_attributes();

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

  script_copyright(english:"Ubuntu Security Notice (C) 2022 Canonical, Inc. / NASL script (C) 2022 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/cpu", "Host/Ubuntu", "Host/Ubuntu/release", "Host/Debian/dpkg-l");

  exit(0);
}

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

if ( ! get_kb_item('Host/local_checks_enabled') ) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
var release = get_kb_item('Host/Ubuntu/release');
if ( isnull(release) ) audit(AUDIT_OS_NOT, 'Ubuntu');
var release = chomp(release);
if (! preg(pattern:"^(16\.04|18\.04|20\.04|21\.04|21\.10)$", string:release)) audit(AUDIT_OS_NOT, 'Ubuntu 16.04 / 18.04 / 20.04 / 21.04 / 21.10', 'Ubuntu ' + release);
if ( ! get_kb_item('Host/Debian/dpkg-l') ) 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$") audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'Ubuntu', cpu);


var pkgs = [
    {'osver': '16.04', 'pkgname': 'libruby2.3', 'pkgver': '2.3.1-2~ubuntu16.04.16+esm2'},
    {'osver': '16.04', 'pkgname': 'ruby2.3', 'pkgver': '2.3.1-2~ubuntu16.04.16+esm2'},
    {'osver': '16.04', 'pkgname': 'ruby2.3-dev', 'pkgver': '2.3.1-2~ubuntu16.04.16+esm2'},
    {'osver': '16.04', 'pkgname': 'ruby2.3-tcltk', 'pkgver': '2.3.1-2~ubuntu16.04.16+esm2'},
    {'osver': '18.04', 'pkgname': 'libruby2.5', 'pkgver': '2.5.1-1ubuntu1.11'},
    {'osver': '18.04', 'pkgname': 'ruby2.5', 'pkgver': '2.5.1-1ubuntu1.11'},
    {'osver': '18.04', 'pkgname': 'ruby2.5-dev', 'pkgver': '2.5.1-1ubuntu1.11'},
    {'osver': '20.04', 'pkgname': 'libruby2.7', 'pkgver': '2.7.0-5ubuntu1.6'},
    {'osver': '20.04', 'pkgname': 'ruby2.7', 'pkgver': '2.7.0-5ubuntu1.6'},
    {'osver': '20.04', 'pkgname': 'ruby2.7-dev', 'pkgver': '2.7.0-5ubuntu1.6'},
    {'osver': '21.04', 'pkgname': 'libruby2.7', 'pkgver': '2.7.2-4ubuntu1.3'},
    {'osver': '21.04', 'pkgname': 'ruby2.7', 'pkgver': '2.7.2-4ubuntu1.3'},
    {'osver': '21.04', 'pkgname': 'ruby2.7-dev', 'pkgver': '2.7.2-4ubuntu1.3'},
    {'osver': '21.10', 'pkgname': 'libruby2.7', 'pkgver': '2.7.4-1ubuntu3.1'},
    {'osver': '21.10', 'pkgname': 'ruby2.7', 'pkgver': '2.7.4-1ubuntu3.1'},
    {'osver': '21.10', 'pkgname': 'ruby2.7-dev', 'pkgver': '2.7.4-1ubuntu3.1'}
];

var flag = 0;
foreach package_array ( pkgs ) {
  var osver = NULL;
  var pkgname = NULL;
  var 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
{
  var tested = ubuntu_pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, 'libruby2.3 / libruby2.5 / libruby2.7 / ruby2.3 / ruby2.3-dev / etc');
}

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-5235-1.nasl
Windows:
C:\ProgramData\Tenable\Nessus\nessus\plugins\ubuntu_USN-5235-1.nasl
Mac OS X:
/Library/Nessus/run/lib/nessus/plugins/ubuntu_USN-5235-1.nasl

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How to Run

Here is how to run the Ubuntu 16.04 LTS / 18.04 LTS / 20.04 LTS / 21.04 / 21.10 : Ruby vulnerabilities (USN-5235-1) 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 16.04 LTS / 18.04 LTS / 20.04 LTS / 21.04 / 21.10 : Ruby vulnerabilities (USN-5235-1) plugin ID 156802.
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-5235-1.nasl -t <IP/HOST>

Run the plugin with audit trail message on the console:

/opt/nessus/bin/nasl -a ubuntu_USN-5235-1.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-5235-1.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-5235-1.nasl -t <IP/HOST>

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References

USN | Ubuntu Security Notice:

5235-1

See also:

Similar and related Nessus plugins:

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156329 - Debian DLA-2853-1 : ruby2.3 - LTS security update
157378 - Debian DSA-5066-1 : ruby2.5 - security update
157380 - Debian DSA-5067-1 : ruby2.7 - security update
159088 - EulerOS 2.0 SP5 : ruby (EulerOS-SA-2022-1337)
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159813 - EulerOS 2.0 SP9 : ruby (EulerOS-SA-2022-1458)
159967 - EulerOS 2.0 SP10 : ruby (EulerOS-SA-2022-1496)
159939 - EulerOS 2.0 SP10 : ruby (EulerOS-SA-2022-1515)
160595 - EulerOS Virtualization 2.9.1 : ruby (EulerOS-SA-2022-1613)
160586 - EulerOS Virtualization 2.9.0 : ruby (EulerOS-SA-2022-1637)
158114 - Oracle Linux 8 : ruby:2.6 (ELSA-2022-0543)
158132 - RHEL 8 : ruby:2.6 (RHSA-2022:0543)
158120 - RHEL 8 : ruby:2.6 (RHSA-2022:0544)
158216 - RHEL 8 : ruby:2.6 (RHSA-2022:0581)
158215 - RHEL 8 : ruby:2.6 (RHSA-2022:0582)
158464 - RHEL 7 : rh-ruby26-ruby (RHSA-2022:0708)
160492 - SUSE SLED15 / SLES15 Security Update : ruby2.5 (SUSE-SU-2022:1512-1)

Version

This page has been produced using Nessus Professional 10.1.2 (#68) LINUX, Plugin set 202205072148.
Plugin file ubuntu_USN-5235-1.nasl version 1.4. For more plugins, visit the Nessus Plugin Library.

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Ubuntu 16.04 LTS / 18.04 LTS / 20.04 LTS / 21.04 / 21.10 : Ruby vulnerabilities (USN-5235-1) - Nessus

Plugin Overview

Vulnerability Information

Synopsis

Description

Solution

Public Exploits

Risk Information

Plugin Source

How to Run

References

Version

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