Amazon Linux 2 : unbound (ALASUNBOUND-1.17-2024-003)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Amazon Linux 2 Security Advisory ALASUNBOUND-1.17-2024-003.
##

include('compat.inc');

if (description)
{
  script_id(209066);
  script_version("1.2");
  script_set_attribute(attribute:"plugin_modification_date", value:"2024/10/25");

  script_cve_id("CVE-2024-8508");
  script_xref(name:"IAVA", value:"2024-A-0682");

  script_name(english:"Amazon Linux 2 : unbound (ALASUNBOUND-1.17-2024-003)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Amazon Linux 2 host is missing a security update.");
  script_set_attribute(attribute:"description", value:
"The version of unbound installed on the remote host is prior to 1.17.0-2. It is, therefore, affected by a vulnerability
as referenced in the ALAS2UNBOUND-1.17-2024-003 advisory.

    NLnet Labs Unbound up to and including version 1.21.0 contains a vulnerability when handling replies with
    very large RRsets that it needs to perform name compression for. Malicious upstreams responses with very
    large RRsets can cause Unbound to spend a considerable time applying name compression to downstream
    replies. This can lead to degraded performance and eventually denial of service in well orchestrated
    attacks. The vulnerability can be exploited by a malicious actor querying Unbound for the specially
    crafted contents of a malicious zone with very large RRsets. Before Unbound replies to the query it will
    try to apply name compression which was an unbounded operation that could lock the CPU until the whole
    packet was complete. Unbound version 1.21.1 introduces a hard limit on the number of name compression
    calculations it is willing to do per packet. Packets that need more compression will result in semi-
    compressed packets or truncated packets, even on TCP for huge messages, to avoid locking the CPU for long.
    This change should not affect normal DNS traffic. (CVE-2024-8508)

Tenable has extracted the preceding description block directly from the tested product security advisory.

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://alas.aws.amazon.com/AL2/ALASUNBOUND-1.17-2024-003.html");
  script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/cve/html/CVE-2024-8508.html");
  script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/faqs.html");
  script_set_attribute(attribute:"solution", value:
"Run 'yum update unbound' to update your system.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/I:N/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:N/I:N/A:L");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2024-8508");

  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:"2024/10/03");
  script_set_attribute(attribute:"patch_publication_date", value:"2024/10/10");
  script_set_attribute(attribute:"plugin_publication_date", value:"2024/10/15");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:python2-unbound");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:python3-unbound");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:unbound");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:unbound-anchor");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:unbound-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:unbound-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:unbound-libs");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:unbound-utils");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:amazon:linux:2");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_set_attribute(attribute:"stig_severity", value:"II");
  script_end_attributes();

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

  script_copyright(english:"This script is Copyright (C) 2024 and is owned by Tenable, Inc. or an Affiliate thereof.");

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

  exit(0);
}

include("rpm.inc");

if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);

var alas_release = get_kb_item("Host/AmazonLinux/release");
if (isnull(alas_release) || !strlen(alas_release)) audit(AUDIT_OS_NOT, "Amazon Linux");
var os_ver = pregmatch(pattern: "^AL(A|\d+|-\d+)", string:alas_release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, "Amazon Linux");
os_ver = os_ver[1];
if (os_ver != "2")
{
  if (os_ver == 'A') os_ver = 'AMI';
  audit(AUDIT_OS_NOT, "Amazon Linux 2", "Amazon Linux " + os_ver);
}

if (!get_kb_item("Host/AmazonLinux/rpm-list")) audit(AUDIT_PACKAGE_LIST_MISSING);

var pkgs = [
    {'reference':'python2-unbound-1.17.0-2.amzn2.0.5', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'unbound-1.17'},
    {'reference':'python2-unbound-1.17.0-2.amzn2.0.5', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'unbound-1.17'},
    {'reference':'python3-unbound-1.17.0-2.amzn2.0.5', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'unbound-1.17'},
    {'reference':'python3-unbound-1.17.0-2.amzn2.0.5', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'unbound-1.17'},
    {'reference':'unbound-1.17.0-2.amzn2.0.5', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'unbound-1.17'},
    {'reference':'unbound-1.17.0-2.amzn2.0.5', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'unbound-1.17'},
    {'reference':'unbound-anchor-1.17.0-2.amzn2.0.5', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'unbound-1.17'},
    {'reference':'unbound-anchor-1.17.0-2.amzn2.0.5', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'unbound-1.17'},
    {'reference':'unbound-debuginfo-1.17.0-2.amzn2.0.5', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'unbound-1.17'},
    {'reference':'unbound-debuginfo-1.17.0-2.amzn2.0.5', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'unbound-1.17'},
    {'reference':'unbound-devel-1.17.0-2.amzn2.0.5', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'unbound-1.17'},
    {'reference':'unbound-devel-1.17.0-2.amzn2.0.5', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'unbound-1.17'},
    {'reference':'unbound-libs-1.17.0-2.amzn2.0.5', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'unbound-1.17'},
    {'reference':'unbound-libs-1.17.0-2.amzn2.0.5', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'unbound-1.17'},
    {'reference':'unbound-utils-1.17.0-2.amzn2.0.5', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'unbound-1.17'},
    {'reference':'unbound-utils-1.17.0-2.amzn2.0.5', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'unbound-1.17'}
];

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;
  var cves = NULL;
  if (!empty_or_null(package_array['reference'])) reference = package_array['reference'];
  if (!empty_or_null(package_array['release'])) _release = 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 (!empty_or_null(package_array['cves'])) cves = package_array['cves'];
  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, cves:cves)) flag++;
  }
}

if (flag)
{
  security_report_v4(
      port       : 0,
      severity   : SECURITY_WARNING,
      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, "python2-unbound / python3-unbound / unbound / etc");
}