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nessusThis script is Copyright (C) 2021 and is owned by Tenable, Inc. or an Affiliate thereof.XEN_SERVER_XSA-286.NASL
HistoryJan 19, 2021 - 12:00 a.m.

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

2021-01-1900:00:00
This script is Copyright (C) 2021 and is owned by Tenable, Inc. or an Affiliate thereof.
www.tenable.com
16

5.3 Medium

CVSS3

Attack Vector

LOCAL

Attack Complexity

LOW

Privileges Required

LOW

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

LOW

Integrity Impact

LOW

Availability Impact

LOW

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L

4.6 Medium

CVSS2

Access Vector

Access Complexity

Authentication

NONE

Confidentiality Impact

PARTIAL

Integrity Impact

PARTIAL

Availability Impact

PARTIAL

AV:L/AC:L/Au:N/C:P/I:P/A:P

0.0005 Low

EPSS

Percentile

17.5%

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.

##
# (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);
VendorProductVersionCPE
xenxencpe:/o:xen:xen

5.3 Medium

CVSS3

Attack Vector

LOCAL

Attack Complexity

LOW

Privileges Required

LOW

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

LOW

Integrity Impact

LOW

Availability Impact

LOW

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L

4.6 Medium

CVSS2

Access Vector

Access Complexity

Authentication

NONE

Confidentiality Impact

PARTIAL

Integrity Impact

PARTIAL

Availability Impact

PARTIAL

AV:L/AC:L/Au:N/C:P/I:P/A:P

0.0005 Low

EPSS

Percentile

17.5%