Xen Hypervisor Pin Count / Page Reference Grant Table Code Guest-to-Host Memory Corruption (XSA-236)

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

include("compat.inc");

if (description)
{
  script_id(104214);
  script_version("1.7");
  script_set_attribute(attribute:"plugin_modification_date", value:"2021/06/03");

  script_cve_id("CVE-2017-15597");
  script_bugtraq_id(101564);
  script_xref(name:"IAVB", value:"2017-B-0148-S");

  script_name(english:"Xen Hypervisor Pin Count / Page Reference Grant Table Code Guest-to-Host Memory Corruption (XSA-236)");
  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 memory corruption
vulnerability. This may allow an attacker on the guest to cause a
denial of service or 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.xenproject.org/xsa/advisory-236.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:N/AC:L/Au:S/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:N/AC:L/PR:H/UI:N/S:C/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-2017-15597");

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

  script_set_attribute(attribute:"vuln_publication_date", value:"2017/10/24");
  script_set_attribute(attribute:"patch_publication_date", value:"2017/10/24");
  script_set_attribute(attribute:"plugin_publication_date", value:"2017/10/27");

  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-236
fixes['4.5']['fixed_ver']           = '4.5.5';
fixes['4.5']['fixed_ver_display']   = '4.5.5 (changeset 08aa260)';
fixes['4.5']['affected_ver_regex']  = '^4\\.5\\.';
fixes['4.5']['affected_changesets'] = make_list("03b06d3", "77666b6",
  "bbeb763", "5fdf16f", "0e9967d", "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 9454e30)';
fixes['4.6']['affected_ver_regex']  = '^4\\.6\\.';
fixes['4.6']['affected_changesets'] = make_list("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']           = '4.7.4';
fixes['4.7']['fixed_ver_display']   = '4.7.4-pre (changeset f03b9e8)';
fixes['4.7']['affected_ver_regex']  = '^4\\.7\\.';
fixes['4.7']['affected_changesets'] = make_list("df0949d", "c10dc54",
  "8cd1258", "1d01ddc", "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 fcbbd0f)';
fixes['4.8']['affected_ver_regex']  = '^4\\.8\\.';
fixes['4.8']['affected_changesets'] = make_list("0c647de", "bdc2ae6",
  "96e6364", "1a8ad09", "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 174a569)';
fixes['4.9']['affected_ver_regex']  = '^4\\.9\\.';
fixes['4.9']['affected_changesets'] = make_list("2040ac1", "de38e28",
  "7fe0a24", "a2af47d", "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);