Xen Device Quarantine for Alternate PCI Assignment Methods Privilege Escalation Vulnerability (XSA-306)

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

include('compat.inc');

if (description)
{
  script_id(134171);
  script_version("1.4");
  script_set_attribute(attribute:"plugin_modification_date", value:"2021/01/14");

  script_cve_id("CVE-2019-19579");
  script_xref(name:"IAVB", value:"2019-B-0084-S");

  script_name(english:"Xen Device Quarantine for Alternate PCI Assignment Methods Privilege Escalation Vulnerability (XSA-306)");

  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
privilege escalation vulnerability due to an incomplete fix for CVE-2019-18424. An unauthenticated attacker with
physical access to the device can exploit this issue, via an untrusted domain with access to a physical device to DMA 
into the host memory and potentially gain elevated privileges.");
  # https://xenbits.xen.org/xsa/advisory-306.html
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?047434f7");
  script_set_attribute(attribute:"solution", value:
"Apply the appropriate patch according to the vendor advisory.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:N/C:C/I:C/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/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-2019-19579");

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

  script_set_attribute(attribute:"vuln_publication_date", value:"2019/11/26");
  script_set_attribute(attribute:"patch_publication_date", value:"2019/11/26");
  script_set_attribute(attribute:"plugin_publication_date", value:"2020/03/02");

  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) 2020-2021 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('audit.inc');
include('global_settings.inc');
include('install_func.inc');
include('misc_func.inc');

app_name = 'Xen Hypervisor';
install  = get_single_install(app_name:app_name);
if (report_paranoia < 2) audit(AUDIT_PARANOID);

version         = install['version'];
display_version = install['display_version'];
path            = install['path'];
managed_status  = install['Managed status'];
changeset       = install['Changeset'];

if (!empty_or_null(changeset))
  display_version += ' (changeset ' + changeset + ')';

# Installations that are vendor-managed are handled by OS-specific local package checks
if (managed_status == 'managed')
  audit(AUDIT_INST_PATH_NOT_VULN, app_name, display_version, path);

fixes['4.8']['fixed_ver']           = '4.8.5';
fixes['4.8']['fixed_ver_display']   = '4.8.5 (changeset ec6c25e)';
fixes['4.8']['affected_ver_regex']  = '^4\\.8\\.';
fixes['4.8']['affected_changesets'] = make_list(
'1486caf', '4c666a7', 'a70ba89', '6082eac', 'fb93a9b', '80e67e4', 'dc62982', 'aca2511', '17c3324', '4ffb12e', '929ec99',
'ae9ec06', '6c4efc1', '2867c7e', '611ca5b', '12ac129', 'f1bf612', '422d637', '6699295', '10105fa', 'bf78103', '219b64d',
'f03e1b7', '048bbe8', '151406a', 'd02aeba', '960670a', '4ed28df', 'c67210f', 'd4d3ab3', 'd87211e', 'a9acbcf', '514de95',
'48ab64f', '181ed91', 'c3fdb25', '7feb3cc', '343c611', '257048f', '491e033', '3683ec2', 'a172d06', '52092fc', 'e0d6cde',
'cc1c9e3', 'f6a4af3', 'ece24c0', '175a698', '48f5cf7', '9eb6247', '31cbd18', 'fcf002d', 'ecbf88a', 'd929136', '8099c04',
'752fb21', 'a95a103', '3dcb199', '55da36f', '160f050', '194b7a2', 'a556287', '2032f86', 'e9d860f', 'a1f8fe0', '5bc841c',
'4539dbc', 'dcd6efd', '88fb22b', '1c4ab1e', '40ad83f', '51c3b69', '44aba8b', '067ec7d', 'f51d8e5', 'b9b0c46', '908e768');

fixes['4.9']['fixed_ver']           = '4.9.4';
fixes['4.9']['fixed_ver_display']   = '4.9.4 (changeset e60b3a)';
fixes['4.9']['affected_ver_regex']  = '^4\\.9\\.';
fixes['4.9']['affected_changesets'] = make_list(
'25f5530', '49db55f', 'fa34ed5', '704f7ec', 'a930a74', '8c52ee2', '2e15a19', '70639ac', 'c3b479d', 'e349eae', '632fb4e',
'4608c6d', '7daacca', '859e48e', '5be2dd0', 'b0147bd', 'cadd66a', 'd3c4b60', 'd59f5c4', '44303c6', '79538ba', '80c3157',
'73f1a55', 'bc20fb1', '754a531', '7b032c2', 'ff4fdf0', '8d2a688', 'b9013d7', 'bc8e5ec', '34907f5', 'e70bf7e', 'fa0b891',
'3a8177c', '04ec835', '8d63ec4', '1ff6b4d', 'f092d86', 'e4b534f', '87c49fe', '19becb8', '43775c0', 'f6b0f33', 'a17e75c',
'67530e7', 'f804549', '84f81a8', '56aa239', '105db42', 'd9da3ea', 'ac90240', '3db28b0', '9b6f1c0', '0c4bbad', '917d8d3',
'3384ea4', '352421f', '04e9dcb', '1612f15', 'f952b1d', '63d9330', 'f72414a', 'ac3a5f8', '1ae6b8e', '1dd3dcc', '7390fa1',
'7e78dc4', '8fdfb1e', '55d36e2', '045f37c', 'dd7e637', '7a40b5b', 'f5acf97');

fixes['4.10']['fixed_ver']           = '4.10.4';
fixes['4.10']['fixed_ver_display']   = '4.10.4 (changeset e489955)';
fixes['4.10']['affected_ver_regex']  = '^4\\.10\\.';
fixes['4.10']['affected_changesets'] = make_list(
'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']           = '4.11.3';
fixes['4.11']['fixed_ver_display']   = '4.11.3-pre (changeset 1d6777d)';
fixes['4.11']['affected_ver_regex']  = '^4\\.11\\.';
fixes['4.11']['affected_changesets'] = make_list(
'0eb99bf', '9474622', 'f9ea10d', '48a2e5d', '68c8a75', 'b697438', '7152399', '75de893', 'fd40571', '0a79df7', 'b12609b',
'a08fdb8', '0b1e97d', '41d85cb', '64d6137', '7450704', '56590ac', 'cc06f60', 'eb60ebb', '0db606d', '006b204', 'a187099',
'3697e2a', 'c0f9d1e', '7cb2f1d', '56767b7', '952f362', '7c3c7d8', 'ee78046', '05c14f6', '6fed54c', '766edd7', '657dc2d',
'be89e98', '273cf03', 'd78a967', 'c20ab0c', '5350514', '19bb4f5', 'ca185ab', '0047407', 'aebe055', 'd6d52bc', '317de0a',
'1b16093', 'ce7b549', '621b2d0', '8502a2c', '7f5f48d', '7824b9f', 'b52bcda', '27ff738', '6d36734', 'e2e653f', '9eac932',
'd4fe232', 'ba287c7', 'e33ce32', '28ed7a5', '527e324', '91836ce', '6eb3f76', 'cb86f3d', '8bfcd2e', 'fb1db30', 'b5433e7',
'b6ef69d', 'd27973c', 'ba6f5be', '4c6142e', '6e63afe', '5fcaaae', 'b0d4cec', 'c76e47d', 'a43eb8a', '3342ee9', 'b222046',
'37ccdfd', '8bbb3e9', 'ff5ddf0', '802f994', '10582ea', '4e95d85', 'da235ee', '32bdae2', 'b647da4', '1ec05c2', '9b91bec',
'dc3cd3d', '3311f10', '5fd47c5', '6af54f7', 'c250e2d', '08cb4b9', '8efcc0d', '1cf304f', 'c14026b', 'c719519', '93ad919',
'fcc4f5d', '2f7f16c', 'fddda5d', 'd0dc725', '7ca58e5', 'be800a1');

fixes['4.12']['fixed_ver']           = '4.12.2';
fixes['4.12']['fixed_ver_display']   = '4.12.2-pre (changeset 875879a)';
fixes['4.12']['affected_ver_regex']  = '^4\\.12\\.';
fixes['4.12']['affected_changesets'] = make_list(
'a008435', '3b448cb', '1d64dc7', 'd1a06c9', '1a69ef0', '18f988a', '88d4e37', '36d2ecb', 'ee37d67', 'ece1cb0', 'f4a82a3',
'cf47a0e', '3334cb1', '08fde90', '16f03e0', '58668f1', '0138da1', '12a1ff9', 'a457425', '7f10403', 'b29848b', '278e46a',
'7412e27', '58d59b9', '16bc9c0', '694fa9c', 'df67757', 'bbcd6c5', '7575728', 'db91ac4', '5698505', '28c209e', '1b1295e',
'94ff3cf', '3918f99', '81a0e12', '113282b', '828e277', 'f5af2b9', '09513ab', '3dc7b91', '3d83e00', '26b8dd7', '5572ba9',
'bb4c1a8', '81feea0', '9f74689', '5f1c9e4', '4b5cc95', 'ab1e6a7', '801acf8', '97b4698', 'e28f7d6', '4fe70a1', 'c288534',
'2a8209f', 'bc87a2d', '8fbf991', '8382d02', 'e142459', '0d210c0', '89de994', '9187046', '634a4d3', 'b6ee060', '61770e7',
'599d6d2', '9d73672', 'e6ccef1', '2b84ade', 'd2ca39f', '04a2fe9', '3c10d06', '4e145fd', '07ec556', '847fc70', '5ea346e',
'd42fb06', '32443f6', 'a5fc553', 'b465705', 'd04466f', 'be2cd69', '50b9123', '8b129ba', 'b527557');

fix = NULL;
foreach ver_branch (keys(fixes))
{
  if (version =~ fixes[ver_branch]['affected_ver_regex'])
  {
    ret = ver_compare(ver:version, fix:fixes[ver_branch]['fixed_ver']);
    if (ret < 0)
      fix = fixes[ver_branch]['fixed_ver_display'];
    else if (ret == 0)
    {
      if (empty_or_null(changeset))
        fix = fixes[ver_branch]['fixed_ver_display'];
      else
        foreach affected_changeset (fixes[ver_branch]['affected_changesets'])
          if (changeset == affected_changeset)
            fix = fixes[ver_branch]['fixed_ver_display'];
    }
  }
}

if (empty_or_null(fix))
  audit(AUDIT_INST_PATH_NOT_VULN, app_name, display_version, path);

items  = make_array(
  'Installed version', display_version,
  'Fixed version', fix,
  'Path', path
);

order  = make_list('Path', 'Installed version', 'Fixed version');
report = report_items_str(report_items:items, ordered_fields:order) + '\n';

security_report_v4(port:0, extra:report, severity:SECURITY_HOLE);