Ubuntu 20.04 LTS / 22.04 LTS / 23.04 / 23.10 : python-cryptography vulnerabilities (USN-6539-1)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Ubuntu Security Notice USN-6539-1. 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(186623);
  script_version("1.0");
  script_set_attribute(attribute:"plugin_modification_date", value:"2023/12/06");

  script_cve_id("CVE-2023-23931", "CVE-2023-49083");
  script_xref(name:"USN", value:"6539-1");

  script_name(english:"Ubuntu 20.04 LTS / 22.04 LTS / 23.04 / 23.10 : python-cryptography vulnerabilities (USN-6539-1)");

  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 / 22.04 LTS / 23.04 / 23.10 host has packages installed that are affected by multiple
vulnerabilities as referenced in the USN-6539-1 advisory.

  - cryptography is a package designed to expose cryptographic primitives and recipes to Python developers. In
    affected versions `Cipher.update_into` would accept Python objects which implement the buffer protocol,
    but provide only immutable buffers. This would allow immutable objects (such as `bytes`) to be mutated,
    thus violating fundamental rules of Python and resulting in corrupted output. This now correctly raises an
    exception. This issue has been present since `update_into` was originally introduced in cryptography 1.8.
    (CVE-2023-23931)

  - cryptography is a package designed to expose cryptographic primitives and recipes to Python developers.
    Calling `load_pem_pkcs7_certificates` or `load_der_pkcs7_certificates` could lead to a NULL-pointer
    dereference and segfault. Exploitation of this vulnerability poses a serious risk of Denial of Service
    (DoS) for any application attempting to deserialize a PKCS7 blob/certificate. The consequences extend to
    potential disruptions in system availability and stability. This vulnerability has been patched in version
    41.0.6. (CVE-2023-49083)

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://ubuntu.com/security/notices/USN-6539-1");
  script_set_attribute(attribute:"solution", value:
"Update the affected python-cryptography and / or python3-cryptography packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/I:P/A:P");
  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:L/A:L");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:P/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2023-23931");

  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:"2023/02/07");
  script_set_attribute(attribute:"patch_publication_date", value:"2023/12/06");
  script_set_attribute(attribute:"plugin_publication_date", value:"2023/12/06");

  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:"cpe:/o:canonical:ubuntu_linux:22.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:23.04");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:23.10");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:python-cryptography");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:python3-cryptography");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

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

  script_copyright(english:"Ubuntu Security Notice (C) 2023 Canonical, Inc. / NASL script (C) 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 (! ('20.04' >< os_release || '22.04' >< os_release || '23.04' >< os_release || '23.10' >< os_release)) audit(AUDIT_OS_NOT, 'Ubuntu 20.04 / 22.04 / 23.04 / 23.10', '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': '20.04', 'pkgname': 'python-cryptography', 'pkgver': '2.8-3ubuntu0.2'},
    {'osver': '20.04', 'pkgname': 'python3-cryptography', 'pkgver': '2.8-3ubuntu0.2'},
    {'osver': '22.04', 'pkgname': 'python3-cryptography', 'pkgver': '3.4.8-1ubuntu2.1'},
    {'osver': '23.04', 'pkgname': 'python3-cryptography', 'pkgver': '38.0.4-2ubuntu0.1'},
    {'osver': '23.10', 'pkgname': 'python3-cryptography', 'pkgver': '38.0.4-4ubuntu0.23.10.1'}
];

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_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, 'python-cryptography / python3-cryptography');
}