FreeBSD : Unbound -- Denial of service attack (2368755b-83f6-11ef-8d2e-a04a5edf46d9)

#%NASL_MIN_LEVEL 80900
#
# (C) Tenable, Inc.
#
# @NOAGENT@
#
# The descriptive text and package checks in this plugin were
# extracted from the FreeBSD VuXML database :
#
# Copyright 2003-2021 Jacques Vidrine and contributors
#
# Redistribution and use in source (VuXML) and 'compiled' forms (SGML,
# HTML, PDF, PostScript, RTF and so forth) with or without modification,
# are permitted provided that the following conditions are met:
# 1. Redistributions of source code (VuXML) must retain the above
#    copyright notice, this list of conditions and the following
#    disclaimer as the first lines of this file unmodified.
# 2. Redistributions in compiled form (transformed to other DTDs,
#    published online in any format, converted to PDF, PostScript,
#    RTF and other formats) must reproduce the above copyright
#    notice, this list of conditions and the following disclaimer
#    in the documentation and/or other materials provided with the
#    distribution.
#
# THIS DOCUMENTATION IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
# THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
# PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
# BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
# OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
# OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
# BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
# WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
# OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS DOCUMENTATION,
# EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#

include('compat.inc');

if (description)
{
  script_id(208232);
  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:"FreeBSD : Unbound -- Denial of service attack (2368755b-83f6-11ef-8d2e-a04a5edf46d9)");

  script_set_attribute(attribute:"synopsis", value:
"The remote FreeBSD host is missing one or more security-related updates.");
  script_set_attribute(attribute:"description", value:
"The version of FreeBSD installed on the remote host is prior to tested version. It is, therefore, affected by a
vulnerability as referenced in the 2368755b-83f6-11ef-8d2e-a04a5edf46d9 advisory.

    NLnet labs report:
    A vulnerability has been discovered in Unbound when handling
                replies with very large RRsets that Unbound 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.
    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.

Tenable has extracted the preceding description block directly from the FreeBSD 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://nlnetlabs.nl/news/2024/Oct/03/unbound-1.21.1-released/");
  # https://vuxml.freebsd.org/freebsd/2368755b-83f6-11ef-8d2e-a04a5edf46d9.html
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?d6508a9a");
  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: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:"2024/10/06");
  script_set_attribute(attribute:"plugin_publication_date", value:"2024/10/07");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:freebsd:freebsd:unbound");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:freebsd:freebsd");
  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:"FreeBSD 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/FreeBSD/release", "Host/FreeBSD/pkg_info");

  exit(0);
}


include("freebsd_package.inc");

if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
if (!get_kb_item("Host/FreeBSD/release")) audit(AUDIT_OS_NOT, "FreeBSD");
if (!get_kb_item("Host/FreeBSD/pkg_info")) audit(AUDIT_PACKAGE_LIST_MISSING);


var flag = 0;

var packages = [
    'unbound<1.21.1'
];

foreach var package( packages ) {
    if (pkg_test(save_report:TRUE, pkg: package)) flag++;
}

if (flag)
{
  security_report_v4(
    port       : 0,
    severity   : SECURITY_WARNING,
    extra      : pkg_report_get()
  );
  exit(0);
}
else audit(AUDIT_HOST_NOT, "affected");