Xen Hypervisor PCI MSI Interrupt Setup Multiple Guest-to-Host Privilege Escalation (XSA-237)

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

include("compat.inc");

if (description)
{
  script_id(103972);
  script_version("1.7");
  script_set_attribute(attribute:"plugin_modification_date", value:"2021/06/03");

  script_cve_id(
    "CVE-2017-15588",
    "CVE-2017-15589",
    "CVE-2017-15590",
    "CVE-2017-15591",
    "CVE-2017-15592",
    "CVE-2017-15593",
    "CVE-2017-15594",
    "CVE-2017-15595",
    "CVE-2017-15596"
  );
  script_bugtraq_id(101490, 101496, 101500);
  script_xref(name:"IAVB", value:"2017-B-0142-S");

  script_name(english:"Xen Hypervisor PCI MSI Interrupt Setup Multiple Guest-to-Host Privilege Escalation (XSA-237)");
  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 multiple vulnerabilities
related to the setup of PCI MSI interrupts, which may allow an
attacker on the guest to cause a denial of service on the host,
potentially disclose sensitive information from the host, or
potentially gain elevated privileges on the host.

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-237.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:C/I:C/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:POC/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:P/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2017-15595");

  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");

  script_set_attribute(attribute:"vuln_publication_date", value:"2017/10/12");
  script_set_attribute(attribute:"patch_publication_date", value:"2017/10/12");
  script_set_attribute(attribute:"plugin_publication_date", value:"2017/10/19");

  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) 2017-2021 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);

# XSA-237
fixes['4.5']['fixed_ver']           = '4.5.5';
fixes['4.5']['fixed_ver_display']   = '4.5.5 (changeset 7afc8ad)';
fixes['4.5']['affected_ver_regex']  = '^4\\.5\\.';
fixes['4.5']['affected_changesets'] = make_list("72c107b", "5659aa5",
  "a224de6", "6442fa9", "db487a6", "709230f", "83724d9", "04b8c4c",
  "0b2ceae", "e3f0768", "d5a5231", "c5b0fe5", "136ff4e", "42c8ba5",
  "d38489d", "df59014", "3217129", "4964e86", "c079597", "6ec173b",
  "a373456", "0780e81", "e5ef76d", "25eaa86", "ae02360", "5597df9",
  "c5de05e", "773094e", "e39a248", "7b3712a", "be35327", "8825df1",
  "d7e3725", "6eb61e4", "b1fcfed", "5779d6a", "afdd77e", "c18367a",
  "7b7fd80", "b30e165", "62ef9b2", "8071724", "235b5d5", "a28b99d",
  "ff294fc", "bc01e2d", "da50922", "386cc94", "139960f", "ec3ddd6",
  "988929a", "1c48dff", "20d4248", "9610422", "cd76cd3", "455fd66",
  "b820c31", "ac3d8bc", "cde86fc", "1678521", "83cb2db", "43d06ef",
  "2b17bf4", "1a2bda5", "0bd7faf", "e3426e2", "37281bc", "27be856",
  "bdf3ef1", "cc325c0", "8e7b84d", "387b8ae", "34fbae7", "1530da2",
  "274a1f6", "b679cfa", "877b760", "cfe165d", "84e4e56", "e4ae4b0");

fixes['4.6']['fixed_ver']           = '4.6.6';
fixes['4.6']['fixed_ver_display']   = '4.6.6 (changeset 9bac910)';
fixes['4.6']['affected_ver_regex']  = '^4\\.6\\.';
fixes['4.6']['affected_changesets'] = make_list("c7a43e3", "913d4f8",
  "c5881c5", "b0239cd", "78fd0c3", "9079e0d", "1658a87", "22b6dfa",
  "a8cd231", "629eddd", "64c03bb", "b4660b4", "1ac8162", "747df3c",
  "5ae011e", "f974d32", "3300ad3", "d708b69");

fixes['4.7']['fixed_ver']           = '4.7.4';
fixes['4.7']['fixed_ver_display']   = '4.7.4-pre (changeset e3f7a64)';
fixes['4.7']['affected_ver_regex']  = '^4\\.7\\.';
fixes['4.7']['affected_changesets'] = make_list("957ad23", "b1ae705",
  "3add76f", "314a8fc", "d6aad63", "7c99633", "145c18d", "c3fa5cd",
  "487f8f9", "ffcfc40", "c7783d9", "3331050", "83966a3", "a67b223",
  "68dbba2", "2728470", "dea68ed", "9d12253", "73d7bc5", "b704b1a",
  "ca4ef7b", "ece330a", "3d63ebc", "30d50f8", "2dc3cdb", "5151257",
  "c9f3ca0", "e873251", "8aebf85", "c362cde", "fece08a");

fixes['4.8']['fixed_ver']           = '4.8.3';
fixes['4.8']['fixed_ver_display']   = '4.8.3-pre (changeset 1960ca8)';
fixes['4.8']['affected_ver_regex']  = '^4\\.8\\.';
fixes['4.8']['affected_changesets'] = make_list("866cfa1", "ddd6e41",
  "370cc9a", "39e3024", "9f092f5", "667f70e", "2116fec", "1a535c3",
  "ee3fc24", "d623d82", "dda458c", "c642b12", "80d7ef3", "ff4f60a",
  "36898eb", "4d7ccae", "e574046", "90dafa4", "c020cf2");

fixes['4.9']['fixed_ver']           = '4.9.1';
fixes['4.9']['fixed_ver_display']   = '4.9.1-pre (changeset 44ceb19)';
fixes['4.9']['affected_ver_regex']  = '^4\\.9\\.';
fixes['4.9']['affected_changesets'] = make_list("ae45442", "784afd9",
  "22032b2", "58da67f", "d1b64cc", "9cde7a8", "1cdcb36", "84c039e",
  "b244ac9", "612044a", "e8fd372", "a568e25", "8fef83e", "478e40c",
  "22ea731", "e7703a2", "91ded3b", "2cc3d32", "79775f5", "43cb0c4",
  "4821228", "d23bcc5", "308654c", "6fd84b3", "89b36cc", "a9ecd60",
  "798f6c9", "6508278", "5587d9a", "527fc5c", "5ff1de3", "692ed82",
  "9bf14bb", "c57b1f9", "6b147fd", "0e186e3", "afc5ebf", "266fc0e",
  "4698106", "f4f02f1", "0fada05", "ab4eb6c", "b29ecc7", "a11d14b",
  "107401e", "1b7834a");

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);