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nessusThis script is Copyright (C) 2017-2021 and is owned by Tenable, Inc. or an Affiliate thereof.XEN_SERVER_XSA-242.NASL
HistoryOct 19, 2017 - 12:00 a.m.

Xen Hypervisor Page Type Reference Handling Memory Exhaustion Guest-to-Host DoS (XSA-242)

2017-10-1900:00:00
This script is Copyright (C) 2017-2021 and is owned by Tenable, Inc. or an Affiliate thereof.
www.tenable.com
6

According to its self-reported version number, the Xen hypervisor installed on the remote host is affected by an unspecified flaw in arch/x86/mm.c that is triggered as page type references are not properly handled when performing certain cleanup operations. This allows an attacker on the guest to consume excessive memory, resulting in a denial of service for 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.

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

include("compat.inc");

if (description)
{
  script_id(103977);
  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 Page Type Reference Handling Memory Exhaustion Guest-to-Host DoS (XSA-242)");
  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 an unspecified flaw in
arch/x86/mm.c that is triggered as page type  references are not
properly handled when performing certain cleanup operations. This
allows an attacker on the guest to consume excessive memory, resulting
in a denial of service for 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-242.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-242
fixes['4.5']['fixed_ver']           = '4.5.5';
fixes['4.5']['fixed_ver_display']   = '4.5.5 (changeset 0e9967d)';
fixes['4.5']['affected_ver_regex']  = '^4\\.5\\.';
fixes['4.5']['affected_changesets'] = make_list("da4f24d", "b7582ac",
  "196371c", "7afc8ad", "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 42b2c82)';
fixes['4.6']['affected_ver_regex']  = '^4\\.6\\.';
fixes['4.6']['affected_changesets'] = make_list("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']           = '4.7.4';
fixes['4.7']['fixed_ver_display']   = '4.7.4-pre (changeset 1d01ddc)';
fixes['4.7']['affected_ver_regex']  = '^4\\.7\\.';
fixes['4.7']['affected_changesets'] = make_list("5ca7d11", "ebd47d4",
  "6a6a339", "e61be54", "e3f7a64", "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 1a8ad09)';
fixes['4.8']['affected_ver_regex']  = '^4\\.8\\.';
fixes['4.8']['affected_changesets'] = make_list("df89197", "c4f969d",
  "b1f3f1d", "7251c06", "1960ca8", "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 a2af47d)';
fixes['4.9']['affected_ver_regex']  = '^4\\.9\\.';
fixes['4.9']['affected_changesets'] = make_list("61a2d31", "c2b0a92",
  "d842630", "ef61bcf", "44ceb19", "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);
VendorProductVersion
xenxen