Xen arch/x86/x86_64/entry.S Exception Handling Guest-to-host DoS (XSA-259)

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

include("compat.inc");

if (description)
{
  script_id(109574);
  script_version("1.5");
  script_set_attribute(attribute:"plugin_modification_date", value:"2021/06/03");

  script_cve_id("CVE-2018-10471");
  script_bugtraq_id(104003);
  script_xref(name:"IAVB", value:"2018-B-0057-S");

  script_name(english:"Xen arch/x86/x86_64/entry.S Exception Handling Guest-to-host DoS (XSA-259)");
  script_summary(english:"Checks '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 a denial of service
vulnerability.

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.");
  script_set_attribute(attribute:"see_also", value:"http://xenbits.xen.org/xsa/advisory-259.html");
  script_set_attribute(attribute:"see_also", value:"https://xenbits.xen.org/gitweb/?p=xen.git;a=summary");
  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:N/I:N/A:C");
  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:C/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-2018-10471");

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

  script_set_attribute(attribute:"vuln_publication_date", value:"2018/04/25");
  script_set_attribute(attribute:"patch_publication_date", value:"2018/04/25");
  script_set_attribute(attribute:"plugin_publication_date", value:"2018/05/04");

  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) 2018-2021 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['4.6']['fixed_ver']           = '4.6.6';
fixes['4.6']['fixed_ver_display']   = '4.6.6 (changeset 927aca7)';
fixes['4.6']['affected_ver_regex']  = '^4\\.6\\.';
fixes['4.6']['affected_changesets'] = make_list("b4b553d", "b766574",
  "10898d7", "0b38930", "33f70b8", "cf03d32", "525c381", "4c1e2d3",
  "021009e", "4972c38", "bd461fc", "c9c1bb6", "0fbf30a", "7e20b9b",
  "d1618f4", "9d534c1", "dbb3553", "e54a8c6", "8005ed3", "9a852e0",
  "d779cc1", "c93bcf9", "15adcf3", "d7b8190", "2b1457f", "a357880",
  "ee23fcc", "5651015", "225e9c7", "3c70619", "1222333", "75bdd69",
  "8994cf3", "642c603", "c25ea9a", "feba571", "0163087", "44c2666",
  "db743b0", "41a5cce", "4e1b9e9", "4d21549", "ff4800c", "2613a1b",
  "8335c8a", "ab20c5c", "9089da9", "8edfc82", "af5b61a", "ec05090",
  "75263f7", "f7e273a", "03c7d2c", "9ce1a71", "a735c7a", "44ad7f6",
  "91dc902", "a065841", "c6e9e60", "f94c11d", "45ddc4e", "1ca93b7",
  "8c0c36e", "6e43623", "47d3e73", "ea80245", "37bb22b", "9b0c2a2",
  "8d3fe28", "be63d66", "9454e30", "aad5a67", "d8b0ebf", "f0208a4",
  "42b2c82", "57318e1", "9f22d72", "e0353b4", "76f1549", "9bac910",
  "c7a43e3", "913d4f8", "c5881c5", "b0239cd", "78fd0c3", "9079e0d",
  "1658a87", "22b6dfa", "a8cd231", "629eddd", "64c03bb", "b4660b4",
  "1ac8162", "747df3c", "5ae011e", "f974d32", "3300ad3", "d708b69");

fixes['4.7']['fixed_ver']           = '4.7.5';
fixes['4.7']['fixed_ver_display']   = '4.7.5 (changeset a8ef075)';
fixes['4.7']['affected_ver_regex']  = '^4\\.7\\.';
fixes['4.7']['affected_changesets'] = make_list("e613050", "2fbc006",
  "1619cff", "5c81317", "912aa9b", "63b140f", "62b1879", "9680710", "dca80ab");

fixes['4.8']['fixed_ver']           = '4.8.4';
fixes['4.8']['fixed_ver_display']   = '4.8.4-pre (changeset 1052a21)';
fixes['4.8']['affected_ver_regex']  = '^4\\.8\\.';
fixes['4.8']['affected_changesets'] = make_list("a2f02df", "501718a",
  "957ff30", "1e9ac23", "95befc6", "372583c", "202aaf8", "e4e9632",
  "a753be1", "8f9846f", "0864795", "866deda", "c67e19f", "bc6414f",
  "883c8db", "7db1c43", "813fe21", "3cadc8b", "f7bf4d2", "14217cb",
  "ce185fb", "a2700ca", "b19b206", "a442d40", "1901f62", "1581910",
  "15f57b8", "7ef31c0", "bc8aa42", "30a153d", "da92664", "6b08396",
  "f6ae9c0", "ad9ddc3", "22d2146", "f9adc12", "e27fd5c", "03f9474",
  "c31070f", "1093876", "141be84", "bb49733", "48faa50", "5938aa1",
  "d11783c", "8e1e3c7", "99ed786", "76bdfe8", "fee4689", "c0bfde6",
  "64c1742", "8615385", "e09a5c2", "ff570a3", "e6bcb41", "29e7171",
  "c3d195c", "2cd189e", "afdad6a", "532ccf4", "da49e51", "ca9583d",
  "479b879", "2eefd92", "60c50f2", "1838e21", "5732a8e", "987b08d",
  "eadcd83", "ef2464c", "17bfbc8", "499391b", "87cb0e2", "393de92");

fixes['4.9']['fixed_ver']           = '4.9.3';
fixes['4.9']['fixed_ver_display']   = '4.9.3-pre (changeset 7866e11)';
fixes['4.9']['affected_ver_regex']  = '^4\\.9\\.';
fixes['4.9']['affected_changesets'] = make_list("db7accf", "921bff4",
  "c147505", "dc527ff", "781e23a", "72ca580", "47d41f6", "7a59015",
  "259bee9", "6d4c4f0", "3e010f5");

fixes['4.10']['fixed_ver']           = '4.10.1';
fixes['4.10']['fixed_ver_display']   = '4.10.1-pre (changeset cba8690)';
fixes['4.10']['affected_ver_regex']  = '^4\\.10\\.';
fixes['4.10']['affected_changesets'] = make_list("d27de97", "656c147",
  "8d37ee1", "696b24d", "41015e7", "4f12a18", "649e617", "bd26592",
  "afece29", "2e34343", "d9756ca", "e2ee191", "2efc116", "51742fb",
  "4fcd9d1", "1ef0574", "ee109ad", "b2682ed", "9746779", "1d99ad5",
  "9beb8a4", "ef4b4d7", "df71252", "7f9ebeb", "4eb96e3", "3087ba8",
  "76a6ddd", "0f92968", "9e9185f", "e87e798", "6131a2c", "47621a4",
  "489cfbc", "860f470", "8462c57", "cee48d8", "20db434", "0d2f9c8",
  "a1189f9", "c37114c", "5ede9f9", "7e0796d", "b9aa790", "4867afb",
  "3deb58f", "3376822", "37dd907", "2967058", "0857b09", "4195d40",
  "ab62fc3", "0e10f28", "a05fc8e", "083bd83", "b0e975c", "def2940",
  "8c3bbc7", "cee8bb6", "08a941b", "7dc817b", "2108084", "dc4a23b",
  "da7543d", "9fd27db", "6d9b6bf", "79f0429", "9ce99ad", "186c2f5",
  "357bf02", "81306ed", "14e1a43", "b869742", "d691e41", "ee478f4",
  "f05a7c5", "7027acf", "bc513e8", "af63193", "a44e83b", "da3a46d",
  "b6a6458", "e3dfd5d", "a6780c1", "16edf98", "e2ceb2e", "1b1c059",
  "5e91fc4", "3921128", "cd2e143", "3181472", "5644514", "db12743",
  "bc0e599", "fc81946", "ce7d7c0", "a695f8d", "92efbe8", "8baba87",
  "79891ef", "641c11e", "05eba93", "a69cfdf", "0f4be6e", "0a7e6b5",
  "65ee6e0", "129880d", "c513244", "0e12c2c", "6aaf353", "32babfc",
  "47bbcb2", "8743fc2", "1830b20", "ab95cb0", "d02ef3d", "e32f814",
  "c534ab4", "be3138b", "79012ea", "bbd093c", "a69a8b5", "f167ebf",
  "c4c0187", "19ad8a7", "3caf32c", "df7be94", "f379b70", "728fadb",
  "9281129", "cae6e15", "d1f4283", "0f7a4fa", "b829d42", "fa23f2a",
  "79f797c", "69f4d87", "7cccd6f", "234f481", "57dc197", "7209b8b",
  "910dd00", "50d24b9", "c89c622", "3b8d88d", "6f1979c", "0a515ee",
  "0e2d64a", "ab9e385", "abdde49", "321ef98", "c9083de", "b5be9c8",
  "9d60bc9", "29dd314", "5b6c3ff", "004646a", "7dcc20e", "83c838c",
  "cc7d96b", "7f5eb7d", "bbad376", "da4518c", "1cd7039", "60dd953",
  "0ba5d8c", "4ba6447", "2b8a95a", "cdb1fb4", "a401864", "3784256",
  "b5ead1f", "aa96a59", "7477359", "cb5dc94", "3b058a3", "5a543c6",
  "949eb11", "f5ca369", "68e7a08", "d2df09c", "efa15c9", "83186a8",
  "1fa5444", "10128f3", "2f5a012", "9752c74", "b38cc15", "3d1afab",
  "31b664a", "db65173", "51f937a", "887c705", "f575701", "af2f50b",
  "b538a13", "57dc22b", "48811d4", "78898c9", "e7c8187", "9e46ae1",
  "ff1fb8f", "92a6295", "78e9cc3", "6672750", "4621c10", "40938b5",
  "5840f40", "caff7f9", "69e302e", "a87ec48", "9dc5eda", "135b67e",
  "682a9d8", "19dcd8e", "e5364c3", "e2dc7b5", "c8f4f45", "4150501",
  "ab7be6c", "f3fb667");

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);