Xen: x86: BTC/SRSO Fixes Not Fully Effective (XSA-446)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable Inc.
##

include('compat.inc');

if (description)
{
  script_id(186415);
  script_version("1.4");
  script_set_attribute(attribute:"plugin_modification_date", value:"2024/01/15");

  script_cve_id("CVE-2023-46836");
  script_xref(name:"IAVB", value:"2023-B-0090");

  script_name(english:"Xen: x86: BTC/SRSO Fixes Not Fully Effective (XSA-446)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Xen hypervisor installation is missing a security update.");
  script_set_attribute(attribute:"description", value:
"The fixes for XSA-422 (Branch Type Confusion) and XSA-434 (Speculative Return Stack Overflow) are not IRQ-safe as it
was believed that the mitigations were always operated in contexts with IRQs disabled. However due to an unanticipated
interaction with XSA-254 (Meltdown), a race condition exists whereby a malicious guest can bypass BTC/SRSO protections.
As a result, an attacker in a PV guest can infer the contents of memory belonging to other guests.

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-445.html");
  script_set_attribute(attribute:"solution", value:
"Apply the appropriate patch according to the vendor advisory.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:H/Au:S/C:C/I:N/A:N");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2023-46836");

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

  script_set_attribute(attribute:"vuln_publication_date", value:"2023/11/14");
  script_set_attribute(attribute:"patch_publication_date", value:"2023/11/14");
  script_set_attribute(attribute:"plugin_publication_date", value:"2023/11/29");

  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) 2023-2024 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');

var fixes;
var app = 'Xen Hypervisor';
var app_info = vcf::xen_hypervisor::get_app_info(app:app);
if (report_paranoia < 2) audit(AUDIT_PARANOID);

fixes['4.15']['fixed_ver']           = '4.15.5';
fixes['4.15']['fixed_ver_display']   = '4.15.5 (changeset b918c4c)';
fixes['4.15']['affected_ver_regex']  = "^4\.15([^0-9]|$)";
fixes['4.15']['affected_changesets'] = make_list('1f5f515', '4a4daf6',
  '1f0d217', 'c844124', '75aa1c9', '9a502b6', '3ab7e4a', '609b76c',
  '844bcf0', 'ff2ba13', '586aab2', '964840a', '8c1075d', '60aed4c',
  '1b8dbe4', '0a70ce9', '3a9a290', 'd7b7804', 'b007f82', 'dac9060',
  'd39e5cf', 'd75cb6d', '93504b3', '67b9743', '806893a', '094cd5c',
  'db3386e', '0517763', 'da7f151');

fixes['4.16']['fixed_ver']           = '4.16.5';
fixes['4.16']['fixed_ver_display']   = '4.16.5 (changeset 4dfe951)';
fixes['4.16']['affected_ver_regex']  = "^4\.16([^0-9]|$)";
fixes['4.16']['affected_changesets'] = make_list('6fea383', '29efce0',
  '3c22a9b', 'a157b71', '5182683', '1395852', 'c1159b5', 'd01f651',
  '4f46a07', '3d760a3', '7661261', '2de503f', '7d520b8', 'd51a2a1',
  '35217b7', '3382512', 'c450a4b', 'de751c3', 'a5857f1', '3e51782',
  '8064cbd', '19aca8f', '6cc49c3', '353e876', 'afa5b17', '1e52cdf',
  '08539e8', 'd720c23', 'b9ad687');

fixes['4.17']['fixed_ver']           = '4.17.3';
fixes['4.17']['fixed_ver_display']   = '4.17.3-pre (changeset 0311ff4)';
fixes['4.17']['affected_ver_regex']  = "^4\.17([^0-9]|$)";
fixes['4.17']['affected_changesets'] = make_list('b7a1e10', '0b56bed',
  '3f8b444', '46d00db', '42bf49d', 'f5e2116', '8ee1924', '3797742',
  'e7059f1', '8a58412', 'eb4efda', '78143c5', 'f1cd620', 'd665c66',
  '0d8f9f7', 'c4e05c9', '90c540c', '9ac2f49', '19ee1e1', '2e2c3ef',
  'e4a71bc', '5f7efd4', 'ba023e9', '3952c73', '84690fb', 'dc28aba',
  'd2d2dca', 'd31e5b2', '699de51', '8be85d8', 'a939e95', '7ca58fb',
  '0429822', 'ba360fb', '5116fe1', 'e08e733', '1bd4523', 'a885649',
  'd0cdd34', 'f04295d', 'e5f9987', '7b5155a', '052a8d2', 'f00d563',
  'e418a77', '24487fe', 'ae1045c', '37f1d68', '476d262', 'a1f68fb',
  '36e84ea', '56076ef', '1c3927f', '8d84be5', '7d88979', '2f337a0');

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