XENMEM_aquire_resources Error Path DoS (XSA-334)

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

include('compat.inc');

if (description)
{
  script_id(144794);
  script_version("1.3");
  script_set_attribute(attribute:"plugin_modification_date", value:"2021/06/03");

  script_cve_id("CVE-2020-25598");
  script_xref(name:"IAVB", value:"2020-B-0056-S");

  script_name(english:"XENMEM_aquire_resources Error Path DoS (XSA-334)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Xen hypervisor installation is missing a security update.");
  script_set_attribute(attribute:"description", value:
"A denial of service (DoS) vulnerability exists in Xen servers XENMEM_acquire_resource due to an error path exiting 
without releasing an RCU (Read, Copy, Update) reference. An authenticated, local attacker can exploit this issue, via 
a malicious HVM stubdomain which can cause an RCU reference to be leaked, that leads to subsequent administration 
operations, (e.g. CPU offline) to livelock, resulting in a host DoS.");
  script_set_attribute(attribute:"see_also", value:"https://xenbits.xen.org/xsa/advisory-334.html");
  script_set_attribute(attribute:"solution", value:
"Apply the appropriate patch or mitigation as described in the vendor advisory.");
  script_set_cvss_base_vector("CVSS2#AV:L/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:L/AC:L/PR:L/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-2020-25598");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_cwe_id(670);

  script_set_attribute(attribute:"vuln_publication_date", value:"2020/09/22");
  script_set_attribute(attribute:"patch_publication_date", value:"2020/09/22");
  script_set_attribute(attribute:"plugin_publication_date", value:"2021/01/07");

  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_extras.inc');

app = 'Xen Hypervisor';

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

if (report_paranoia < 2) audit(AUDIT_PARANOID);

fixes['4.12']['fixed_ver']           = '4.12.4';
fixes['4.12']['fixed_ver_display']   = '4.12.4-pre (changeset 8b8fff2)';
fixes['4.12']['affected_ver_regex']  = "^4\.12\.";
fixes['4.12']['affected_changesets'] = make_list('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 286b353)';
fixes['4.13']['affected_ver_regex']  = "^4\.13\.";
fixes['4.13']['affected_changesets'] = make_list('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 5eab5f0)';
fixes['4.14']['affected_ver_regex']  = "^4\.14\.";
fixes['4.14']['affected_changesets'] = make_list('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_NOTE);