Ubuntu 16.04 LTS / 18.04 LTS / 20.04 LTS : Ruby vulnerabilities (USN-4882-1)

##
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Ubuntu Security Notice USN-4882-1. 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(147970);
  script_version("1.4");
  script_set_attribute(attribute:"plugin_modification_date", value:"2023/10/16");

  script_cve_id("CVE-2020-10663", "CVE-2020-10933", "CVE-2020-25613");
  script_xref(name:"USN", value:"4882-1");

  script_name(english:"Ubuntu 16.04 LTS / 18.04 LTS / 20.04 LTS : Ruby vulnerabilities (USN-4882-1)");

  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 / 20.10 host has packages installed that are affected by multiple
vulnerabilities as referenced in the USN-4882-1 advisory.

  - The JSON gem through 2.2.0 for Ruby, as used in Ruby 2.4 through 2.4.9, 2.5 through 2.5.7, and 2.6 through
    2.6.5, has an Unsafe Object Creation Vulnerability. This is quite similar to CVE-2013-0269, but does not
    rely on poor garbage-collection behavior within Ruby. Specifically, use of JSON parsing methods can lead
    to creation of a malicious object within the interpreter, with adverse effects that are application-
    dependent. (CVE-2020-10663)

  - An issue was discovered in Ruby 2.5.x through 2.5.7, 2.6.x through 2.6.5, and 2.7.0. If a victim calls
    BasicSocket#read_nonblock(requested_size, buffer, exception: false), the method resizes the buffer to fit
    the requested size, but no data is copied. Thus, the buffer string provides the previous value of the
    heap. This may expose possibly sensitive data from the interpreter. (CVE-2020-10933)

  - An issue was discovered in Ruby through 2.5.8, 2.6.x through 2.6.6, and 2.7.x through 2.7.1. WEBrick, a
    simple HTTP server bundled with Ruby, had not checked the transfer-encoding header value rigorously. An
    attacker may potentially exploit this issue to bypass a reverse proxy (which also has a poor header
    check), which may lead to an HTTP Request Smuggling attack. (CVE-2020-25613)

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-4882-1");
  script_set_attribute(attribute:"solution", value:
"Update the affected packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/I:P/A:N");
  script_set_cvss_temporal_vector("CVSS2#E:POC/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:P/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2020-25613");

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

  script_set_attribute(attribute:"vuln_publication_date", value:"2020/04/28");
  script_set_attribute(attribute:"patch_publication_date", value:"2021/03/18");
  script_set_attribute(attribute:"plugin_publication_date", value:"2021/03/23");

  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:"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) 2021-2023 Canonical, Inc. / NASL script (C) 2021-2023 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('debian_package.inc');

if ( ! get_kb_item('Host/local_checks_enabled') ) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
var os_release = get_kb_item('Host/Ubuntu/release');
if ( isnull(os_release) ) audit(AUDIT_OS_NOT, 'Ubuntu');
os_release = chomp(os_release);
if (! ('16.04' >< os_release || '18.04' >< os_release || '20.04' >< os_release)) audit(AUDIT_OS_NOT, 'Ubuntu 16.04 / 18.04 / 20.04', 'Ubuntu ' + os_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$" && 's390' >!< cpu && 'aarch64' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'Ubuntu', cpu);

var pkgs = [
    {'osver': '16.04', 'pkgname': 'libruby2.3', 'pkgver': '2.3.1-2~ubuntu16.04.15'},
    {'osver': '16.04', 'pkgname': 'ruby2.3', 'pkgver': '2.3.1-2~ubuntu16.04.15'},
    {'osver': '16.04', 'pkgname': 'ruby2.3-dev', 'pkgver': '2.3.1-2~ubuntu16.04.15'},
    {'osver': '16.04', 'pkgname': 'ruby2.3-tcltk', 'pkgver': '2.3.1-2~ubuntu16.04.15'},
    {'osver': '18.04', 'pkgname': 'libruby2.5', 'pkgver': '2.5.1-1ubuntu1.8'},
    {'osver': '18.04', 'pkgname': 'ruby2.5', 'pkgver': '2.5.1-1ubuntu1.8'},
    {'osver': '18.04', 'pkgname': 'ruby2.5-dev', 'pkgver': '2.5.1-1ubuntu1.8'},
    {'osver': '20.04', 'pkgname': 'libruby2.7', 'pkgver': '2.7.0-5ubuntu1.3'},
    {'osver': '20.04', 'pkgname': 'ruby2.7', 'pkgver': '2.7.0-5ubuntu1.3'},
    {'osver': '20.04', 'pkgname': 'ruby2.7-dev', 'pkgver': '2.7.0-5ubuntu1.3'}
];

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_WARNING,
    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');
}