ISC BIND DNAME Recursion DoS (CVE-2021-25215)

##
# (C) Tenable Network Security, Inc.
##

include('compat.inc');

if (description)
{
  script_id(149211);
  script_version("1.4");
  script_set_attribute(attribute:"plugin_modification_date", value:"2021/11/09");

  script_cve_id("CVE-2021-25215");
  script_xref(name:"IAVA", value:"2021-A-0206-S");

  script_name(english:"ISC BIND DNAME Recursion DoS (CVE-2021-25215)");

  script_set_attribute(attribute:"synopsis", value:
"The remote name server is affected by a denial of service vulnerability.");
  script_set_attribute(attribute:"description", value:
"According to its self-reported version, the ISC Bind present on the remote
host is affected by a denial of service vulnerability:

 - DNAME records, described in RFC 6672, provide a way to redirect a subtree
 of the domain name tree in the DNS.  A flaw in the way named processes these
 records may trigger an attempt to add the same RRset to the ANSWER section
 more than once.  When a vulnerable version of named receives a query for a
 record triggering the flaw, the named process will terminate due to a failed
 assertion check.

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://kb.isc.org/v1/docs/CVE-2021-25215");
  script_set_attribute(attribute:"solution", value:
"Upgrade to the patched release most closely related to your current version of BIND.");
  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:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2021-25215");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");

  script_set_attribute(attribute:"vuln_publication_date", value:"2021/04/28");
  script_set_attribute(attribute:"patch_publication_date", value:"2021/04/28");
  script_set_attribute(attribute:"plugin_publication_date", value:"2021/04/30");

  script_set_attribute(attribute:"potential_vulnerability", value:"true");
  script_set_attribute(attribute:"plugin_type", value:"remote");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:isc:bind");
  script_set_attribute(attribute:"stig_severity", value:"I");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"DNS");

  script_copyright(english:"This script is Copyright (C) 2021 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("bind_version.nasl");
  script_require_keys("bind/version", "Settings/ParanoidReport");

  exit(0);
}

include('vcf.inc');
include('vcf_extras.inc');

# Workaround exists
if (report_paranoia < 2)
  audit(AUDIT_PARANOID);

vcf::bind::initialize();

app_info = vcf::get_app_info(app:'BIND', port:53, kb_ver:'bind/version', service:TRUE, proto:'UDP');

constraints = [
  { 'min_version' : '9.0.0', 'max_version' : '9.11.29', 'fixed_display' : '9.11.31' },
  { 'min_version' : '9.12.0', 'max_version' : '9.16.13', 'fixed_display' : '9.16.15'},
  { 'min_version' : '9.9.3-S1', 'max_version' : '9.11.29-S1', 'fixed_display' : '9.11.31-S1' },
  { 'min_version' : '9.16.8-S1', 'max_version' : '9.16.13-S1', 'fixed_display' : '9.16.15-S1'},
  { 'min_version' : '9.17.0', 'max_version' : '9.17.11', 'fixed_display' : '9.17.12'}
];
constraints = vcf::bind::filter_constraints(constraints:constraints, version:app_info.version);

vcf::check_version_and_report(app_info:app_info, constraints:constraints, severity:SECURITY_WARNING);