NSD version Directive Remote Version Disclosure

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


include("compat.inc");


if (description)
{
  script_id(38849);
  script_version("1.11");
  script_cvs_date("Date: 2019/11/22");


  script_name(english:"NSD version Directive Remote Version Disclosure");
  script_summary(english:"Checks the response of a VERSION.BIND request");

  script_set_attribute(attribute:"synopsis", value:"It is possible to obtain the version number of the remote DNS server.");
  script_set_attribute(attribute:"description", value:
"The remote host is running Name Server Daemon (NSD), an open source
DNS server.  It is possible to extract the version number of the
remote installation by sending a special DNS request for the text
'version.bind' in the domain 'chaos'.");
  script_set_attribute(attribute:"see_also", value:"https://www.nlnetlabs.nl/projects/nsd/about/");
  script_set_attribute(attribute:"solution", value:
"It is possible to hide the version number of NSD by adding the
following line to the server section of nsd.conf :

  hide-version: yes");
  script_set_attribute(attribute:"risk_factor", value:"None");

  script_set_attribute(attribute:"plugin_publication_date", value:"2009/05/21");

  script_set_attribute(attribute:"plugin_type", value:"remote");
  script_set_attribute(attribute:"cpe", value: "cpe:/a:nlnetlabs:nsd");
  script_set_attribute(attribute:"asset_inventory", value:"True");
  script_end_attributes();

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

  script_copyright(english:"This script is Copyright (C) 2009-2019 and is owned by Tenable, Inc. or an Affiliate thereof.");

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

  exit(0);
}


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


version = get_kb_item("bind/version");
if (isnull(version)) exit(0);

match = eregmatch(string:version, pattern:"^NSD ([0-9.]+)$", icase:TRUE);
if (isnull(match)) exit(0);

ver_num = match[1];
set_kb_item(name:"nsd/version", value:ver_num);
report = string(
  "\n",
  "The version of the remote NSD server is :\n\n",
  version
);
security_note(port:53, proto:"udp", extra:report);