Zyxel USG FLEX H Series Firewall 1.20 < 1.32 Privilege Escalation

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
##

include('compat.inc');

if (description)
{
  script_id(237021);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2025/05/21");

  script_cve_id("CVE-2025-1731");
  script_xref(name:"IAVA", value:"2025-A-0295");

  script_name(english:"Zyxel USG FLEX H Series Firewall 1.20 < 1.32 Privilege Escalation");

  script_set_attribute(attribute:"synopsis", value:
"The remote security gateway is affected by multiple privilege escalation vulnerabilities.");
  script_set_attribute(attribute:"description", value:
"Firmware version of the Zyxel USG is less than uOS 1.32. This means the Zyxel device is vulnerable to mualtiple
privilege escalation vulnerability. The incorrect permission assignment vulnerability in the PostgreSQL commands 
of certain USG FLEX H series uOS firmware versions could allow an authenticated local attacker with low privileges 
to gain access to the Linux shell and escalate their privileges by crafting malicious scripts or modifying system 
configurations with administrator-level access through a stolen token. Note that modifying the system configuration 
is only possible if the administrator has not logged out and the token remains valid. 

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version
number.");
  # https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-incorrect-permission-assignment-and-improper-privilege-management-vulnerabilities-in-usg-flex-h-series-firewalls-04-22-2025
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?a10e5b38");
  script_set_attribute(attribute:"solution", value:
"Upgrade to Zyxel USG uOS 1.32 or later.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:S/C:C/I:C/A:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2025-1731");

  script_set_attribute(attribute:"vuln_publication_date", value:"2025/04/22");
  script_set_attribute(attribute:"patch_publication_date", value:"2025/04/22");
  script_set_attribute(attribute:"plugin_publication_date", value:"2025/05/21");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/h:zyxel:usg_flex");
  script_set_attribute(attribute:"stig_severity", value:"I");
  script_end_attributes();

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

  script_copyright(english:"This script is Copyright (C) 2025 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("zyxel_usg_detect.nbin");
  script_require_keys("installed_sw/Zyxel Unified Security Gateway (USG)");
  script_require_ports("Host/Zyxel/USG/uos");

  exit(0);
}

include('vcf.inc');

var app = 'Zyxel Unified Security Gateway (USG)';

var app_info = vcf::get_app_info(app:app);

var model = app_info['Model'];
var constraints = [];

if(empty_or_null(model))
  audit(AUDIT_OS_CONF_UNKNOWN, 'Zyxel device');

if ('USG FLEX' >< model && 'H' >< model) 
  constraints = [{'min_version': '1.20', 'fixed_version' : '1.32'}];
else 
  audit(AUDIT_NOT_INST, 'Zyxel USG FLEX H Series Device');

vcf::check_version_and_report(
    app_info:app_info,
    constraints:constraints,
    severity:SECURITY_WARNING
);