Xen INVLPG-like flushes may leave stale TLB entries privilege escalation (XSA-286)

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

include('compat.inc');

if (description)
{
  script_id(145062);
  script_version("1.3");
  script_set_attribute(attribute:"plugin_modification_date", value:"2021/06/03");

  script_cve_id("CVE-2020-27674");
  script_xref(name:"IAVB", value:"2020-B-0056-S");

  script_name(english:"Xen INVLPG-like flushes may leave stale TLB entries privilege escalation (XSA-286)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Xen hypervisor installation is missing a security update.");
  script_set_attribute(attribute:"description", value:
"A privilege escalation vulnerability exists in Xen x86 PV guest kernels due to mishandles invalidation of TLB entries
An unauthenticated, local attacker x86 PV guest OS users to gain guest OS privileges by modifying kernel memory contents, 
because invalidation of TLB entries is mishandled during use of an INVLPG-like attack technique.

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-286.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:P/I:P/A:P");
  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:L/UI:N/S:U/C:L/I:L/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-2020-27674");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_cwe_id(119);

  script_set_attribute(attribute:"vuln_publication_date", value:"2020/10/20");
  script_set_attribute(attribute:"patch_publication_date", value:"2020/10/20");
  script_set_attribute(attribute:"plugin_publication_date", value:"2021/01/19");

  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:"I");
  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 78d903e)';
fixes['4.10']['affected_ver_regex']  = "^4\.10\.";
fixes['4.10']['affected_changesets'] = make_list('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 e274c8b)';
fixes['4.11']['affected_ver_regex']  = "^4\.11\.";
fixes['4.11']['affected_changesets'] = make_list('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-pre (changeset 4100d46)';
fixes['4.12']['affected_ver_regex']  = "^4\.12\.";
fixes['4.12']['affected_changesets'] = make_list('b1d6f37', '0108b01',
  '5d49509', 'f49fff9', '7488b40', 'a938205', '68ff540', '1833c60', 
  '14b0a08', '97f9def', 'b402e2a', '37f45de', 'e461318', '1cec253', 
  '03926de', '6888017', '0186e76', '0ca821f', 'cfd61e6', '2aa4864', 
  '8e25d52', '9c2a027', '9dda47c', 'b8c9776', '253a1e6', '3e039e1', 
  'b2db007', '1dfd2e2', '76a0760', 'd28c52e', '8b8fff2', '320e7a7', 
  '0446e3d', 'a81e655', 'caebaf3', '76d9349', '81564c4', 'ff79981', 
  '3186568', '40e0cf8', 'fbf016f', '8c1c3e7', '5bd49ca', 'e0bd899', 
  'c481b9f', '1336ca1', 'dca9cc7', '07fd5d3', '85ce36d', 'df9a0ad', 
  '7cce3f2', '43258ce', 'a1aae54', 'df11056', '19e0bbb', 'd96c0f1', 
  '653811e', '26072a5', 'b292255', '38dc269', '5733de6', 'd69f305', 
  '8faa45e', '731bdaf', 'ec57b9a', 'a634229', '050fe48', '436ec68', 
  '96e8aba', '7cdc0cf', 'd937532', '7641573', '7eed533', '74a1230', 
  '946113a', '6182e5d', 'ad20170', '218a19b', 'aca68b9', '1f581f9', 
  '4969f34', 'ed44947', '2eb277e', 'b3af150', 'f769c99', 'bcdaffc', 
  '2b10a32', 'a022f36', 'dd49ddf', 'bc775d0', 'be5c240');

fixes['4.13']['fixed_ver']           = '4.13.2';
fixes['4.13']['fixed_ver_display']   = '4.13.2-pre (changeset 28b7817)';
fixes['4.13']['affected_ver_regex']  = "^4\.13\.";
fixes['4.13']['affected_changesets'] = make_list('c10b293', 'dc38c11',
  'b05fe15', '82a2874', 'c32e9be', 'fa9e1f7', 'ca95985', '055a5d5', 
  'ff1fd42', 'e891c28', '3009e4d', '1c86c83', '745652f', '6e237b6', 
  '98ec971', '7f5d676', 'a2c0c91', '8e7e585', '88f5b41', 'f63b20a', 
  'b015fbe', '54becf6', '43572a4', '2105429', 'a8122e9', 'e1364e0', 
  '5867a14', '0537543', 'ae922b9', 'f27980a', 'b7fcbe0', '42fcdd4', 
  '286b353', 'b980319', 'aa1d9a7', 'bd63ab5', '4fb1ad7', '4a0c174', 
  '6ef4dad', 'c663fa5', '761e8df', '6469039', 'b908343', 'ac4ec48', 
  'a7f0434', '0861885', '9b367b2', 'e182965', 'befa216', 'e9e72fb', 
  'b67bb90', 'fff1874', 'ec972cb', 'd967a2b', '665f5c1', 'ddb6fd3', 
  '378321b', '572e349', '0c8c10d', '493e143', '8b9be8f', 'f1055a2', 
  '005d5ea', '1c7a98c', '2b34d8c', '56e117f', '7a76deb', '3e41b72', 
  '9f7e8ba', 'cdd8f95', 'a9d46ba', '05ba427', '780d376', '31c5d84', 
  '27d4f1a', '11ea967', '53bafb5', 'b4afe05', '74ce65c', '0243559', 
  '8ad99de', 'ea7e8d2', '350aaca', 'c3eea2c', '0523225', '672976c', 
  'a6f2080', 'c437e06', '0a85f84', '85ac008', '7f6b66d', '04aedf4', 
  'f2ad77b', 'd61fef6', 'eccc242', '6bfb364', 'bdddd33', '7d57caa', 
  'd74eb10', '9eec3ee', 'd112db3', '333519f');

fixes['4.14']['fixed_ver']           = '4.14.1';
fixes['4.14']['fixed_ver_display']   = '4.14.1-pre (changeset 10bb63c)';
fixes['4.14']['affected_ver_regex']  = "^4\.14\.";
fixes['4.14']['affected_changesets'] = make_list('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);