Xen Hypervisor Memory Leak on Boot (XSA-235)

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

include("compat.inc");

if (description)
{
  script_id(103700);
  script_version("1.8");
  script_set_attribute(attribute:"plugin_modification_date", value:"2021/06/03");

  script_xref(name:"IAVB", value:"2017-B-0134-S");

  script_name(english:"Xen Hypervisor Memory Leak on Boot (XSA-235)");
  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 flaw within the
page_alloc.c and asm-arm/numa.h due to not scrubbing the memory on
boot. This could potentially leave sensitive information available to
read after a reboot.

This issue only affects ARM systems. x86 systems are not affected.

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-245.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:N/C:P/I:N/A:N");
  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:L/I:N/A:N");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");

  script_set_attribute(attribute:"vuln_publication_date", value:"2017/09/28");
  script_set_attribute(attribute:"patch_publication_date", value:"2017/09/28");
  script_set_attribute(attribute:"plugin_publication_date", value:"2017/10/06");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:xen:xen");
  script_set_attribute(attribute:"potential_vulnerability", value:"true");
  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 Tenable Network Security, Inc.");

  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-245
fixes['4.5']['fixed_ver']           = '4.5.5';
fixes['4.5']['fixed_ver_display']   = '4.5.5 (changeset db487a6)';
fixes['4.5']['affected_ver_regex']  = '^4\\.5\\.';
fixes['4.5']['affected_changesets'] = make_list("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 78fd0c3)';
fixes['4.6']['affected_ver_regex']  = '^4\\.6\\.';
fixes['4.6']['affected_changesets'] = make_list("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 d6aad63)';
fixes['4.7']['affected_ver_regex']  = '^4\\.7\\.';
fixes['4.7']['affected_changesets'] = make_list("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 2116fec)';
fixes['4.8']['affected_ver_regex']  = '^4\\.8\\.';
fixes['4.8']['affected_changesets'] = make_list("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 1cdcb36)';
fixes['4.9']['affected_ver_regex']  = '^4\\.9\\.';
fixes['4.9']['affected_changesets'] = make_list("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_WARNING);