CBL Mariner 2.0 Security Update: PyYAML (CVE-2020-1747)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
##

include('compat.inc');

if (description)
{
  script_id(185501);
  script_version("1.0");
  script_set_attribute(attribute:"plugin_modification_date", value:"2023/11/13");

  script_cve_id("CVE-2020-1747");

  script_name(english:"CBL Mariner 2.0 Security Update: PyYAML (CVE-2020-1747)");

  script_set_attribute(attribute:"synopsis", value:
"The remote CBL Mariner host is missing one or more security updates.");
  script_set_attribute(attribute:"description", value:
"The version of PyYAML installed on the remote CBL Mariner 2.0 host is prior to tested version. It is, therefore,
affected by a vulnerability as referenced in the CVE-2020-1747 advisory.

  - A vulnerability was discovered in the PyYAML library in versions before 5.3.1, where it is susceptible to
    arbitrary code execution when it processes untrusted YAML files through the full_load method or with the
    FullLoader loader. Applications that use the library to process untrusted input may be vulnerable to this
    flaw. An attacker could use this flaw to execute arbitrary code on the system by abusing the
    python/object/new constructor. (CVE-2020-1747)

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://nvd.nist.gov/vuln/detail/CVE-2020-1747");
  script_set_attribute(attribute:"solution", value:
"Update the affected packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C");
  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-2020-1747");

  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:"2020/03/19");
  script_set_attribute(attribute:"patch_publication_date", value:"2023/11/02");
  script_set_attribute(attribute:"plugin_publication_date", value:"2023/11/13");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:microsoft:cbl-mariner:PyYAML");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:microsoft:cbl-mariner:PyYAML-debuginfo");
  script_set_attribute(attribute:"cpe", value:"x-cpe:/o:microsoft:cbl-mariner");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

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

  script_copyright(english:"This script is Copyright (C) 2023 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/CBLMariner/release", "Host/CBLMariner/rpm-list", "Host/cpu");

  exit(0);
}
include('rpm.inc');

if (!get_kb_item('Host/local_checks_enabled')) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
var release = get_kb_item('Host/CBLMariner/release');
if (isnull(release) || 'CBL-Mariner' >!< release) audit(AUDIT_OS_NOT, 'CBL-Mariner');
var os_ver = pregmatch(pattern: "CBL-Mariner ([0-9]+(\.[0-9]+)?)", string:release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, 'CBL-Mariner');
os_ver = os_ver[1];
if (! preg(pattern:"^2([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, 'CBL-Mariner 2.0', 'CBL-Mariner ' + os_ver);

if (!get_kb_item('Host/CBLMariner/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$" && 'aarch64' >!< cpu)
  audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'CBL-Mariner', cpu);

var pkgs = [
    {'reference':'PyYAML-5.4.1-1.cm2', 'cpu':'x86_64', 'release':'2.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'PyYAML-5.4.1-1.cm2', 'cpu':'aarch64', 'release':'2.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'PyYAML-debuginfo-5.4.1-1.cm2', 'cpu':'x86_64', 'release':'2.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'PyYAML-debuginfo-5.4.1-1.cm2', 'cpu':'aarch64', 'release':'2.0', '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 = 'CBLMariner-' + 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, 'PyYAML / PyYAML-debuginfo');
}