Oracle Linux 8 : unbound (ELSA-2023-2771)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Oracle Linux Security Advisory ELSA-2023-2771.
##

include('compat.inc');

if (description)
{
  script_id(176303);
  script_version("1.0");
  script_set_attribute(attribute:"plugin_modification_date", value:"2023/05/24");

  script_cve_id("CVE-2022-3204");

  script_name(english:"Oracle Linux 8 : unbound (ELSA-2023-2771)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Oracle Linux host is missing a security update.");
  script_set_attribute(attribute:"description", value:
"The remote Oracle Linux 8 host has packages installed that are affected by a vulnerability as referenced in the
ELSA-2023-2771 advisory.

  - A vulnerability named 'Non-Responsive Delegation Attack' (NRDelegation Attack) has been discovered in
    various DNS resolving software. The NRDelegation Attack works by having a malicious delegation with a
    considerable number of non responsive nameservers. The attack starts by querying a resolver for a record
    that relies on those unresponsive nameservers. The attack can cause a resolver to spend a lot of
    time/resources resolving records under a malicious delegation point where a considerable number of
    unresponsive NS records reside. It can trigger high CPU usage in some resolver implementations that
    continually look in the cache for resolved NS records in that delegation. This can lead to degraded
    performance and eventually denial of service in orchestrated attacks. Unbound does not suffer from high
    CPU usage, but resources are still needed for resolving the malicious delegation. Unbound will keep trying
    to resolve the record until hard limits are reached. Based on the nature of the attack and the replies,
    different limits could be reached. From version 1.16.3 on, Unbound introduces fixes for better performance
    when under load, by cutting opportunistic queries for nameserver discovery and DNSKEY prefetching and
    limiting the number of times a delegation point can issue a cache lookup for missing records.
    (CVE-2022-3204)

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://linux.oracle.com/errata/ELSA-2023-2771.html");
  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:N/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:N/I:N/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-2022-3204");

  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:"2022/09/23");
  script_set_attribute(attribute:"patch_publication_date", value:"2023/05/24");
  script_set_attribute(attribute:"plugin_publication_date", value:"2023/05/24");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:oracle:linux:8");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:python3-unbound");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:unbound");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:unbound-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:unbound-libs");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Oracle Linux 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/OracleLinux", "Host/RedHat/release", "Host/RedHat/rpm-list", "Host/local_checks_enabled");

  exit(0);
}


include('rpm.inc');

if (!get_kb_item('Host/local_checks_enabled')) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
if (!get_kb_item('Host/OracleLinux')) audit(AUDIT_OS_NOT, 'Oracle Linux');
var os_release = get_kb_item("Host/RedHat/release");
if (isnull(os_release) || !pregmatch(pattern: "Oracle (?:Linux Server|Enterprise Linux)", string:os_release)) audit(AUDIT_OS_NOT, 'Oracle Linux');
var os_ver = pregmatch(pattern: "Oracle (?:Linux Server|Enterprise Linux) .*release ([0-9]+(\.[0-9]+)?)", string:os_release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, 'Oracle Linux');
os_ver = os_ver[1];
if (! preg(pattern:"^8([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, 'Oracle Linux 8', 'Oracle Linux ' + os_ver);

if (!get_kb_item('Host/RedHat/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, 'Oracle Linux', cpu);

var pkgs = [
    {'reference':'python3-unbound-1.16.2-5.el8', 'cpu':'aarch64', 'release':'8', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'unbound-1.16.2-5.el8', 'cpu':'aarch64', 'release':'8', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'unbound-devel-1.16.2-5.el8', 'cpu':'aarch64', 'release':'8', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'unbound-libs-1.16.2-5.el8', 'cpu':'aarch64', 'release':'8', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'unbound-devel-1.16.2-5.el8', 'cpu':'i686', 'release':'8', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'unbound-libs-1.16.2-5.el8', 'cpu':'i686', 'release':'8', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'python3-unbound-1.16.2-5.el8', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'unbound-1.16.2-5.el8', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'unbound-devel-1.16.2-5.el8', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'unbound-libs-1.16.2-5.el8', 'cpu':'x86_64', 'release':'8', '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 = 'EL' + 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) {
    if (exists_check) {
        if (rpm_exists(release:_release, rpm:exists_check) && 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++;
    } else {
        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, 'python3-unbound / unbound / unbound-devel / etc');
}