Xen Project XSA-240 Mitigation Shadow Paging Conflict Vulnerability (XSA-280)

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

include("compat.inc");

if (description)
{
  script_id(119660);
  script_version("1.4");
  script_set_attribute(attribute:"plugin_modification_date", value:"2021/06/03");

  script_cve_id("CVE-2018-19966");
  script_bugtraq_id(106182);
  script_xref(name:"IAVB", value:"2018-B-0149-S");

  script_name(english:"Xen Project XSA-240 Mitigation Shadow Paging Conflict Vulnerability (XSA-280)");
  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 vulnerability allowing
a guest system to potentially elevate privileges, access protected
information, and perform a DoS against the host. A number of caveats
exist to determine if a system is vulnerable. Please refer to the
vendor advisory for more information.

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-280.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:U/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:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2018-19966");

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

  script_set_attribute(attribute:"vuln_publication_date", value:"2018/11/20");
  script_set_attribute(attribute:"patch_publication_date", value:"2018/11/20");
  script_set_attribute(attribute:"plugin_publication_date", value:"2018/12/13");

  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) 2018-2021 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);

fixes['4.7']['fixed_ver']           = '4.7.6';
fixes['4.7']['fixed_ver_display']   = '4.7.6 (changeset ab6d56c)';
fixes['4.7']['affected_ver_regex']  = '^4\\.7\\.';
fixes['4.7']['affected_changesets'] = make_list("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['4.8']['fixed_ver']           = '4.8.5';
fixes['4.8']['fixed_ver_display']   = '4.8.5-pre (changeset 92f3118)';
fixes['4.8']['affected_ver_regex']  = '^4\\.8\\.';
fixes['4.8']['affected_changesets'] = make_list("4be61c4", "538c7c7",
  "14854d0", "f030ad0", "d6798ce", "d792e57", "ba4eb85", "88b5e36",
  "64fd42f", "86cba9b", "49f74ea", "5b6fb33", "8d1afd1", "0dbe6ac",
  "38a7dde", "bd89569", "dee5937", "5670039", "53dfcb0", "d4f07fb",
  "005df91", "8bfab2b", "dc814e1", "5e86977", "d1a5936", "c9fc6b3",
  "21ac6c8", "e52ec4b", "d95b5bb", "565de91", "1c6c2de", "1f56fba",
  "5464d5f", "9e7d5e2", "7849d13", "e819108", "fe78829", "28fc483",
  "712082d", "ed6fcdb", "0406164", "e3d0ce3", "c00fabc", "3478439",
  "b81b74a", "b289403", "47fbc6e", "ee7bcea", "df5bbf7", "d96893f",
  "15508b3", "790ed15", "d838957", "aa45015", "b149b06", "c117d09",
  "e343ee8", "5566272", "f049cd6", "6dc0bc5", "37a1b4a", "f6a31ed",
  "08eda97", "96bf2db", "23975f5", "f3b0cdb", "f5ef10d", "de172b0",
  "3686d09", "4aec0c7");

fixes['4.9']['fixed_ver']           = '4.9.4';
fixes['4.9']['fixed_ver_display']   = '4.9.4-pre (changeset ca5ede6)';
fixes['4.9']['affected_ver_regex']  = '^4\\.9\\.';
fixes['4.9']['affected_changesets'] = make_list("d96e629", "d819a65",
  "15b4ee9", "f97a1d1", "f13983d", "8d6f213", "c4a3f16", "1bd7c17",
  "1ebb803", "042887f", "e61a7cb", "f668bb4", "d635520", "b791d9b",
  "273cc99", "ee2e8a0", "f294d80", "782ca9b", "b7dae43", "62ed524",
  "75c8dbc", "56d90f5", "6000494", "870fcbf", "9b31834", "3eabb91");

fixes['4.10']['fixed_ver']           = '4.10.3';
fixes['4.10']['fixed_ver_display']   = '4.10.3-pre (changeset 8b1efc9)';
fixes['4.10']['affected_ver_regex']  = '^4\\.10\\.';
fixes['4.10']['affected_changesets'] = make_list("2f5a67c", "c1fd070",
  "d5d8074", "421aada", "e907460", "ba6ac89", "4c7cd94", "c841c82",
  "5b15c04", "6e3650d", "4d5a0f2", "b0f1b24", "aa05c39", "c504397",
  "1639352", "b79ac27", "5822be6", "225fbd2", "73788eb", "ed024ef",
  "9f8eff3", "788948b", "61dc015", "d86c9ae", "4519790", "5483835",
  "518726d", "d091a49", "923af25", "5ba0bb0", "173c338");

fixes['4.11']['fixed_ver']           = '4.11.1';
fixes['4.11']['fixed_ver_display']   = '4.11.1-pre (changeset bbe48b5)';
fixes['4.11']['affected_ver_regex']  = '^4\\.11\\.';
fixes['4.11']['affected_changesets'] = make_list("93177f1", "e738850",
  "eb6830a", "b88ccb3", "3b2a779", "946f345", "086a9dd", "dea9fc0",
  "ff9f873", "0f0ad14", "8ad462a", "d67b849", "8f3f58c", "06a50b0",
  "fe10c22", "e243639", "f0b4b69", "d34471f", "26feeb5", "221acbf",
  "8bed728", "18b5947", "94fba9f", "33664f9", "a2e35a7", "451f9c8",
  "d7cbb4b", "bb6d070", "b1a47ef", "5b1592d", "0719a5f", "03fd745",
  "d1caf6e", "a07f444", "74fee1b", "2004a91", "8c8b3cb", "5acdd26",
  "733450b", "d757c29", "6c7d074", "2a47c75", "007752f", "fb78137",
  "665e768", "f4a049e", "02d2c66", "57483c0", "d044f6c", "e6441a8",
  "48fb482", "fa79f9e", "1d32c21", "7b420e8", "8b35b97", "cfdd4e8",
  "218d403", "b52017c", "52b8f9a", "935e9c4", "61cc876", "4254e98",
  "6fe9726", "33ced72", "7de2155", "06d2a76", "543027c", "037fe82",
  "353edf1", "75313e4", "5908b48", "bd51a64", "0a2016c", "b53e0de",
  "a44cf0c", "ac35e05", "10c5482", "4bdeedb", "da33530", "e932371", "1fd87ba");

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);