Xen xenstored watch DoS (XSA-324)

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

include('compat.inc');

if (description)
{
  script_id(144713);
  script_version("1.3");
  script_set_attribute(attribute:"plugin_modification_date", value:"2021/06/03");

  script_cve_id("CVE-2020-29484");
  script_xref(name:"IAVB", value:"2020-B-0077-S");

  script_name(english:"Xen xenstored watch DoS (XSA-324)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Xen hypervisor installation is missing a security update.");
  script_set_attribute(attribute:"description", value:
"According to its self-reported version number, the Xen hypervisor installed on the remote host is affected by a denial
of service vulnerability due to an issue with max payload length in xenstored. A malicious guest can exploit this, by
registering a 'watch' with using a very large tag, to cause an error condition in xenstored. This error can result in a
NULL pointer dereference, which can crash xenstored.

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://xenbits.xen.org/xsa/advisory-324.html");
  script_set_attribute(attribute:"solution", value:
"Apply the appropriate patch or workaround according to the vendor advisory.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:N/C:N/I:N/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:L/PR:H/UI:N/S:C/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-2020-29484");

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

  script_set_attribute(attribute:"vuln_publication_date", value:"2020/12/15");
  script_set_attribute(attribute:"patch_publication_date", value:"2020/12/15");
  script_set_attribute(attribute:"plugin_publication_date", value:"2021/01/05");

  script_set_attribute(attribute:"potential_vulnerability", value:"true");
  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:xen:xen");
  script_set_attribute(attribute:"stig_severity", value:"II");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Misc.");

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

  script_dependencies("xen_server_detect.nbin");
  script_require_keys("installed_sw/Xen Hypervisor", "Settings/ParanoidReport");

  exit(0);
}

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

app = 'Xen Hypervisor';

app_info = vcf::xen_hypervisor::get_app_info(app:app);

if (report_paranoia < 2) audit(AUDIT_PARANOID);

fixes['4.10']['fixed_ver']           = '4.10.4';
fixes['4.10']['fixed_ver_display']   = '4.10.4 (changeset 03569ab)';
fixes['4.10']['affected_ver_regex']  = "^4\.10\.";
fixes['4.10']['affected_changesets'] = make_list('17b26b8', '66e2db1',
  'fcc17dc', 'e644edc', '7e16a0e', 'a4c2c94', 'bdd36b6', '59dc712',
  '57a55a4', '03937f9', 'f06e4ac', '3658044', '9edd614', '8cb4d2d',
  '2fee46c', '06092d1', '77d6b2b', 'a043a64', '3afd384', 'e8231b6',
  '1d72d99', '8eb5328', 'f79f47f', 'f91d2a9', '1fdcfdb', '17ec9b4',
  '15b2980', '398f91c', '5114e77', '7a4ec79', '78d903e', '2012db4',
  '71da63b', '56f8da7', 'd73e972', '6f012ec', '75a05da', 'c334b87',
  '07ad8ff', '1719f79', 'f58caa4', 'f2befb6', '83b7f04', 'e081568',
  '7f0793a', '8fac37e', 'baf80b6', '5402540', 'f85223f', '635ae12',
  '3d14937', '4218b74', '93be943', '4418841', 'd9c67d3', '8976bab',
  '388e303', '0b0a155', '9df4399', 'fd57038', 'a9bda69', 'a380168',
  'c1a4914', '6261a06', 'fd6e49e', 'bd20589', 'ce05683', '934d6e1',
  '6e636f2', 'dfc0b23', '2f83654', 'bf467cc', '6df4d40', 'e20bb58',
  'a1a9b05', 'afca67f', 'b922c44', 'b413732', '3d60903', 'b01c84e',
  '1e722e6', '59cf3a0', 'fabfce8', 'a4dd2fe', '6e63a6f', '24d62e1',
  'cbedabf', '38e589d', 'a91b8fc', '3e0c316', '49a5d6e', '6cb1cb9',
  'ba2776a', '9d143e8', 'fe8dab3', '07e546e', 'fefa5f9', 'c9f9ff7',
  '406d40d', 'e489955', '37139f1', 'fde09cb', '804ba02', 'e8c3971',
  'a8c4293', 'aa40452', '1da3dab', 'e5632c4', '902e72d', '6a14610',
  'ea815b2', '13ad331', '61b75d9', 'e70e7bf', 'e966e2e', 'dfa16a1',
  'a71e199', 'c98be9e', 'a548e10', 'd3c0e84', '53b1572', '7203f9a',
  '6d1659d', 'a782173', '24e90db', '0824bc6', 'e6f3135', '3131bf9');

fixes['4.11']['fixed_ver']           = '4.11.4';
fixes['4.11']['fixed_ver_display']   = '4.11.4 (changeset 4053771)';
fixes['4.11']['affected_ver_regex']  = "^4\.11\.";
fixes['4.11']['affected_changesets'] = make_list('b3f4121', 'e36f81f',
  '1034a45', '7791d2e', '5724431', '495e973', '771a105', 'b3f80a3',
  '966f266', '57261ac', '1b7ed67', '0a6bbf9', '6be47ee', '2fe5a55',
  '36621b7', '88f6ff5', '170445f', '550387f', '0297770', 'd2b6bf9',
  '41a822c', '8ab4af9', '4fe1326', '4438fc1', '2a730d5', '62aed78',
  '1447d44', '3b5de11', '65fad0a', 'b5eb495', 'e274c8b', '1d021db',
  '63199df', '7739ffd', '4f35f7f', '490c517', '7912bbe', 'f5ec9f2',
  'ad7d040', '3630a36', '3263f25', '3e565a9', '30b3f29', '3def846',
  'cc1561a', '6e9de08', '13f60bf', '9703a2f', '7284bfa', '2fe163d',
  '2031bd3', '7bf4983', '7129b9e', 'ddaaccb', 'e6ddf4a', 'f2bc74c',
  'd623658', '37c853a', '8bf72ea', '2d11e6d', '4ed0007', '7def72c',
  '18be3aa', 'a3a392e', 'e96cdba', '2b77729', '9be7992', 'b8d476a',
  '1c751c4', '7dd2ac3', 'a58bba2', '7d8fa6a', '4777208', '48e8564',
  '2efca7e', 'afe82f5', 'e84b634', '96a8b5b');

fixes['4.12']['fixed_ver']           = '4.12.4';
fixes['4.12']['fixed_ver_display']   = '4.12.4 (changeset d6d3b13)';
fixes['4.12']['affected_ver_regex']  = "^4\.12\.";
fixes['4.12']['affected_changesets'] = make_list('9fe89e1', 'd009b8d',
  '674108e', 'bfda5ae', '551d75d', '5e1bac4', 'f8443e8', '655190d',
  'f860f42', '9f73020', 'aeebc0c', 'f1a4126', 'b1efedb', '4739f79',
  '0dbcdcc', '444b717', '544a775', 'c64ff3b', '8145d38', '14f577b',
  '40ab019', '1dd870e', '5c15a1c', '6602544', '14c9c0f', 'dee5d47',
  '7b2f479', '46ad884', 'eaafa72', '0e6975b', '8e0c2a2', '51eca39',
  '7ae2afb', '5e11fd5', '34056b2', 'fd4cc0b', '4f9294d', '97b7b55');

fixes['4.13']['fixed_ver']           = '4.13.3';
fixes['4.13']['fixed_ver_display']   = '4.13.3-pre (changeset 18c0abb)';
fixes['4.13']['affected_ver_regex']  = "^4\.13\.";
fixes['4.13']['affected_changesets'] = make_list('782aa4b', '6aea4d8',
  '12a41a8', '4056c3e', 'f4d84a2', '65c187f', '2df79ff', 'b693968',
  '52a0a8f', '60e3727', '8cc0a86', 'ef765f6', 'b8f23da', 'ee416da',
  '1819c9d', '1ab192f', '2007c63', '2948458', '4959626', '2fa586c',
  'b530227', '74c5729', 'a1d8a6c', 'd064b65', '4f30743', '72031bc',
  '7d6f52d', 'ec09215');

fixes['4.14']['fixed_ver']           = '4.14.1';
fixes['4.14']['fixed_ver_display']   = '4.14.1-pre (changeset 7214cc7)';
fixes['4.14']['affected_ver_regex']  = "^4\.14\.";
fixes['4.14']['affected_changesets'] = make_list('49ed711', 'dc871dd',
  'b1c5e40', '61d3863', '9e53440', '335ef5b', '6fa3e05', 'f4405b6',
  '228e562', '0a79a1b', '5073c6b', '5259358', '3d0e1a1', '117521e',
  '91992c7', '4e298fa', '3beffb3', 'da67712', '9c898a8', 'f130d5f',
  '1d1d1f5', '72bd989', '8e6c236', '1cfb9b1', '7c6ee4e', 'd11d977',
  '1ad1773', '0057b1f', 'd101b41', 'd95f450', '73a0927', 'a38060e',
  '78a53f0', '89ae1b1', '7398a44', '59b8366', '1f9f1cb', 'f728b2d',
  '71a12a9', '0c96e42', '29b48aa', 'd131310', '7d2b21f', 'f61c5d0',
  'fc8fab1', '898864c', '9f954ae', '5784d1e', '10bb63c', '941f69a',
  '7b1e587', 'ee47e8e', '4ba3fb0', 'd2ba323', 'b081a5f', 'e936515',
  '9c1cc64', '829dbe2', '8d14800', '0521dc9', '64c3951', '0974e00',
  'a279fcb', 'f7ab0c1', '7339975', '94c157f', '79f1701', '9e757fc',
  '809a70b', 'b427109', 'c93b520', 'f37a1cf', '5478934', '43eceee',
  '03019c2', '66cdf34', 'ecc6428', '2ee270e', '9b9fc8e', 'b8c2efb',
  'f546906', 'eb4a543', 'e417504', '0bc4177', '5ad3152', 'fc8200a',
  '5eab5f0', 'b04d673', '28855eb', '174be04', '158c3bd', '3535f23',
  'de7e543', '483b43c', '431d52a', 'ceafff7', '369e7a3', '98aa6ea',
  '80dec06', '5482c28', 'edf5b86', 'eca6d5e', 'c3a0fc2', '864d570',
  'afed8e4', 'a5dab0a', 'b8c3e33', 'f836759');

vcf::xen_hypervisor::check_version_and_report(app_info:app_info, fixes:fixes, severity:SECURITY_WARNING);