Xen Project PCI Pass-through DMA Privilege Escalation (XSA-288)

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

include("compat.inc");

if (description)
{
  script_id(122872);
  script_version("1.2");
  script_cvs_date("Date: 2019/05/24 15:26:42");


  script_name(english:"Xen Project PCI Pass-through DMA Privilege Escalation (XSA-288)");
  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 privilege escalation
vulnerability. Only x86 systems are 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:"https://xenbits.xen.org/xsa/advisory-288.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:M/Au:N/C:C/I:C/A:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H");
  script_set_attribute(attribute:"cvss_score_source", value:"manual");
  script_set_attribute(attribute:"cvss_score_rationale", value:"Score based on analysis of the vendor advisory.");

  script_set_attribute(attribute:"vuln_publication_date", value:"2019/03/05");
  script_set_attribute(attribute:"patch_publication_date", value:"2019/03/05");
  script_set_attribute(attribute:"plugin_publication_date", value:"2019/03/15");

  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_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Misc.");

  script_copyright(english:"This script is Copyright (C) 2019 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['4.7']['fixed_ver']           = '4.7.6';
fixes['4.7']['fixed_ver_display']   = '4.7.6 (changeset 384a6dd)';
fixes['4.7']['affected_ver_regex']  = '^4\\.7\\.';
fixes['4.7']['affected_changesets'] = make_list("a1500d4", "362cca8",
  "eeea811", "710cc09", "ab6d56c", "4f3858f", "045d4f7", "2b3463f",
  "efe21ad", "9c82759", "3d3e474", "4e69e43", "3d33cc6", "3f7b4ec",
  "7ba1c7d", "87d5aa4", "9b8375a", "da93914", "0aa4696", "f05a33e",
  "f440b31", "1a90803", "0abc1ae", "1fdb25a", "c9641d4", "61c4360",
  "df66c1c", "59732fd", "3f7fd2b", "bcbd8b9", "dfee811", "95ff4e1",
  "ded2a37", "87dba80", "fe028e6", "a51e6a3", "0e66281", "51d9780",
  "91ca84c", "bce2dd6", "fa807e2", "97aff08", "e90e243", "c0e854b",
  "9858a1f", "a404136", "dc111e9", "0873699", "280a556");

fixes['4.10']['fixed_ver']           = '4.10.4';
fixes['4.10']['fixed_ver_display']   = '4.10.4-pre (changeset b450b20)';
fixes['4.10']['affected_ver_regex']  = '^4\\.10\\.';
fixes['4.10']['affected_changesets'] = make_list("dfc7e3c", "382e4a6",
  "edbc9b0", "edb80d2");

fixes['4.11']['fixed_ver']           = '4.11.2';
fixes['4.11']['fixed_ver_display']   = '4.11.2-pre (changeset be58f86)';
fixes['4.11']['affected_ver_regex']  = '^4\\.11\\.';
fixes['4.11']['affected_changesets'] = make_list("4298abd", "4f785ea",
  "1028304", "87f51bf", "dd492b8", "e2e3a1d", "850ca94", "514dccd",
  "e202feb", "1986728", "2cd833d", "de09411", "dd914e4", "63d7113",
  "af25f52", "91f2ad7", "0b2be0b", "7d1bd98", "d8b2418", "bf608fd");

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);