ISC BIND 9.7.0.x < 9.9.6-P2 DNSSEC Validation DoS

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

include("compat.inc");

if (description)
{
  script_id(81489);
  script_version("1.7");
  script_cvs_date("Date: 2018/11/15 20:50:21");

  script_cve_id("CVE-2015-1349");
  script_bugtraq_id(72673);

  script_name(english:"ISC BIND 9.7.0.x < 9.9.6-P2 DNSSEC Validation DoS");
  script_summary(english:"Checks the version of BIND.");

  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 number, the remote installation
of BIND is potentially affected by a denial of service vulnerability
due to an error relating to DNSSEC validation and the managed-keys
feature. A remote attacker can trigger an incorrect trust-anchor
management scenario in which no key is ready for use, resulting in an
assertion failure and daemon crash.

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/article/AA-01245/0/BIND-9.9.6-P2-Release-Notes.html");
  script_set_attribute(attribute:"see_also", value:"https://kb.isc.org/docs/aa-01235");
  script_set_attribute(attribute:"solution", value:
"Upgrade to BIND version 9.9.6-P2 or later.

Alternatively, as a workaround, do not use 'auto' for the
dnssec-validation or dnssec-lookaside options and do not configure a
managed-keys statement.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:H/Au:N/C:N/I:N/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  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:"2015/02/18");
  script_set_attribute(attribute:"patch_publication_date", value:"2015/02/18");
  script_set_attribute(attribute:"plugin_publication_date", value:"2015/02/24");

  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_end_attributes();

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

  script_copyright(english:"This script is Copyright (C) 2015-2018 Tenable Network Security, Inc.");

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

  exit(0);
}

include("audit.inc");
include("global_settings.inc");
include("misc_func.inc");

ver = get_kb_item_or_exit("bind/version");

if (report_paranoia < 2) audit(AUDIT_PARANOID);

# Vuln 9.7.0.x < 9.9.6-P2
# per https://kb.isc.org/docs/aa-01235
if (
  ver =~ "^9\.[78]($|[^0-9])"     ||
  ver =~ "^9\.9\.[0-5]($|[^0-9])" ||
  ver =~ "^9\.9\.6($|([ab][12]|rc[12]|-P1)$)"
)
{
  if (report_verbosity > 0)
  {
    report =
      '\n  Installed version : ' + ver +
      '\n  Fixed version     : 9.9.6-P2' +
      '\n';
    security_warning(port:53, proto:"udp", extra:report);
  }
  else security_warning(port:53, proto:"udp");
}
else audit(AUDIT_LISTEN_NOT_VULN, "BIND", 53, ver, "UDP");