Microsoft Exchange Server Elevation of Privilege Vulnerability (November 2018)

#%NASL_MIN_LEVEL 70300
#
# (C) Tenable Network Security, Inc.
#

include('deprecated_nasl_level.inc');
include('compat.inc');

if (description)
{
  script_id(118978);
  script_version("1.8");
  script_set_attribute(attribute:"plugin_modification_date", value:"2023/04/25");

  script_cve_id("CVE-2018-8581");
  script_bugtraq_id(105837);
  script_xref(name:"CISA-KNOWN-EXPLOITED", value:"2022/03/17");

  script_name(english:"Microsoft Exchange Server Elevation of Privilege Vulnerability (November 2018)");

  script_set_attribute(attribute:"synopsis", value:
"The mail server application on the remote Windows host is affected by
a privilege escalation vulnerability.");
  script_set_attribute(attribute:"description", value:
"The Microsoft Exchange install on the remote host contains an
unspecified flaw that allows an authenticated, man-in-the-middle
attacker to impersonate another user and escalate privileges.");
  # https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2018-8581
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?f97b93f2");
  script_set_attribute(attribute:"solution", value:
"Delete the following registry value :

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa\DisableLoopbackCheck

as shown in the advisory.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:N/C:P/I:P/A:N");
  script_set_cvss_temporal_vector("CVSS2#E:F/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:F/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2018-8581");

  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:"2018/11/13");
  script_set_attribute(attribute:"plugin_publication_date", value:"2018/11/16");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:microsoft:exchange_server");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Windows");

  script_copyright(english:"This script is Copyright (C) 2018-2023 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("microsoft_exchange_installed.nbin");
  script_require_keys("installed_sw/Microsoft Exchange");
  script_require_ports(139, 445);

  exit(0);
}

include("audit.inc");
include("smb_func.inc");
include("smb_hotfixes.inc");
include("smb_hotfixes_fcheck.inc");
include("smb_reg_query.inc");
include("misc_func.inc");
include("install_func.inc");

app = "Microsoft Exchange";
get_install_count(app_name:app, exit_if_zero:TRUE);

registry_init();
hklm = registry_hive_connect(hive:HKEY_LOCAL_MACHINE, exit_on_fail:TRUE);
reg_name = "SYSTEM\CurrentControlSet\Control\Lsa\DisableLoopbackCheck";
reg_value_resp = get_registry_value(handle:hklm, item:reg_name);
err = session_get_errorcode();
RegCloseKey(handle:hklm);
close_registry();

if (isnull(reg_value_resp))
{
  # make sure NULL was returned solely due to the data not existing in the registry
  if (err == ERROR_FILE_NOT_FOUND)
    audit(AUDIT_HOST_NOT, "affected. Registry key 'HKLM:\SYSTEM\CurrentControlSet\Control\Lsa\DisableLoopbackCheck' not found.");
  else
    audit(AUDIT_FN_FAIL, 'get_registry_value', 'error code ' + error_code_to_string(err));
}

port = kb_smb_transport();

reg_name = "HKLM\" + reg_name;
report =
  '\n  Value name : ' + reg_name +
  '\n  Value data : ' + reg_value_resp;
report += '\n';
security_report_v4(port:port, severity:"SECURITY_WARNING", extra:report);