Xen VMentry Failure Denial Of Service vulnerability (XSA-308)

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

include("compat.inc");

if (description)
{
  script_id(132339);
  script_version("1.3");
  script_set_attribute(attribute:"plugin_modification_date", value:"2020/07/10");

  script_cve_id("CVE-2019-19583");
  script_xref(name:"IAVB", value:"2019-B-0091-S");

  script_name(english:"Xen VMentry Failure Denial Of Service vulnerability (XSA-308)");
  script_summary(english:"Checks the 'xl info' output for the Xen hypervisor version.");

  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 an
denial of service vulnerability due to a mishandling of a certain case by VMX VMEntry. An unauthenticated remote 
attacker can exploit this issue, to cause a denial of service (DOS).

Note that Nessus has checked the changeset versions based on the xen.git change log. Nessus did not check guest hardware
configurations or if patches were applied manually to the source code before a recompile and reinstall.");
  # https://xenbits.xen.org/xsa/advisory-308.html
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?3498c20c");
  # https://xenbits.xen.org/gitweb/?p=xen.git;a=summary
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?5e75f4bb");
  script_set_attribute(attribute:"solution", value:
"Apply the appropiate patch according to the vendor advisory.");
  script_set_cvss_base_vector("CVSS2#AV:N/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:N/AC:L/PR:N/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-2019-19583");

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

  script_set_attribute(attribute:"vuln_publication_date", value:"2019/12/11");
  script_set_attribute(attribute:"patch_publication_date", value:"2019/12/11");
  script_set_attribute(attribute:"plugin_publication_date", value:"2019/12/20");

  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) 2019-2020 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 76dad2e)';
fixes['4.8']['affected_ver_regex']  = '^4\\.8\\.';
fixes['4.8']['affected_changesets'] = make_list("714a65a", "d1d3431",
  "a260e93", "ec6c25e", "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 e879bfe)';
fixes['4.9']['affected_ver_regex']  = '^4\\.9\\.';
fixes['4.9']['affected_changesets'] = make_list("ce126c9", "4b69427",
  "8d1ee9f", "e60b3a9", "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 fefa5f9)';
fixes['4.10']['affected_ver_regex']  = '^4\\.10\\.';
fixes['4.10']['affected_changesets'] = make_list("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-pre (changeset d4a67be)';
fixes['4.11']['affected_ver_regex']  = '^4\\.11\\.';
fixes['4.11']['affected_changesets'] = make_list("b8a8278", "06555fd");
  

fixes['4.12']['fixed_ver']           = '4.12.2';
fixes['4.12']['fixed_ver_display']   = '4.12.2-pre (changeset 268e5f6)';
fixes['4.12']['affected_ver_regex']  = '^4\\.12\\.';
fixes['4.12']['affected_changesets'] = make_list("0e3fd5d", "212b850",
  "2590905", "4a0187b", "cfc7ff1", "54e3018", "1e8932f", "3488f26", 
  "08473cf", "acaf498", "40aaf77", "6ef9471", "dde68d8", "7275095", 
  "3f224c9", "1f6bbde", "99bc12e", "0a69b62", "e10c1fb", "e3ea01d", 
  "c5a0891", "1f86e9a", "ee55d9e", "b971da6", "28f34ab", "2caa419", 
  "26d307a", "6b88ada", "4e893a4", "3236f62", "c88640c", "a00325a", 
  "6a66c54", "0b22b83", "f0b9b67", "a387799", "1cb2d60", "875879a", 
  "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");

fixes['4.13']['fixed_ver']           = '4.13.0';
fixes['4.13']['fixed_ver_display']   = '4.13.0-rc (changeset f919dca)';
fixes['4.13']['affected_ver_regex']  = '^4\\.13\\.';
fixes['4.13']['affected_changesets'] = make_list("d8538f7", "fd31193",
  "b0f0bbc", "c6c74e3", "b789dd9", "fd9bfab", "8ba4cd9", "c1299c1", 
  "d7abfd2", "ea6a2c4", "78e7c2e", "8ba357f", "7a0e35f", "b9d5e03", 
  "308d78b", "eb6b000", "d4d4c87", "1d758bc", "e2585f8", "943c74b", 
  "81ecb38", "5655ce8", "56348df", "9a400d1", "72580a8", "195b79a", 
  "34c1172", "5530782", "3f1a53b", "4859911", "ba2ab00", "8c79c12", 
  "77beba7", "8f48634", "c568b11", "183f354", "ca4cd36", "d7cd999", 
  "df7a193", "83ac5ab", "a7b88f0", "9678167", "7059afb", "534f9e2", 
  "a0bfdf6", "0d2791b", "bad237d", "0273d8e", "f710b76", "dde3135", 
  "3afbd23", "e28eed5", "5a870b0", "f3e4fb5", "66b9765", "31c16a8", 
  "5f7e950", "e7c3202", "4abbac1", "b92a286", "65d1049", "f06d11d", 
  "a72c508", "f43afb0", "7b4c3d0", "09242da", "85e1424", "c67c43c", 
  "8c43308", "070e8ce", "0cafb89", "59e89cd", "6dacdcd", "d13dfb0", 
  "8f1d6c0", "aaef3d9", "3683290", "cda8f7e", "0c2a550", "0aaad75", 
  "ad59145", "dedcb10", "6de848f", "70fcd1e", "a458d3b", "2e2356c", 
  "f9e10a9", "f11fda9", "7afbbca", "6378a4c", "ba165e7", "92f91d2", 
  "efee8ba", "df12595", "adaecef", "354b0f2", "32e1956", "38533d9", 
  "0ae2491", "dfdb006", "ae2f94c", "abb234b", "5751861", "0f45bbb", 
  "ed13221", "7e4404f", "3ed885a", "61b6835", "a7b81b0", "6eeef7e", 
  "319f9a0", "31b4f4a", "6e8e163", "88aaf40", "c40b33d", "3c15a2d", 
  "2f12624", "d28fe10", "18b0ab6", "ff0b9a5", "2aab06d", "0121588", 
  "1b6fa63", "bf656e0", "3165ffe", "93021cb", "0bf9f8d", "ece1d5c", 
  "b362c51", "2d6f36d", "8a74707", "f51d4a1", "1a3b393", "cbe572d", 
  "368375d", "2a474dc", "7d2655f", "07149d9", "1666939", "dfcccc6", 
  "4945041", "86cf0ed", "dc2aaaf", "09348b0", "ecec150", "0e606c1", 
  "7b1e233", "64b5d83", "9633929", "333d741", "ad011ad", "95596f6", 
  "5f135a6", "af5c475", "5dedc18", "67c82f4", "a9af7cd", "2541fcc", 
  "3f21bd4", "c399983", "4f05a0c", "818927e", "3f82eb9", "7eee9c1", 
  "529a76f", "9257c21", "b7fab13", "8dea470", "a7ecdf8", "8d4f1b8", 
  "08e2059", "8dba9a8", "228a025", "59d03d2", "6da80b2", "00fc900", 
  "4c555ec", "55ab292", "e370582", "951ab40", "518c935");

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_WARNING);