Multiple AVM FRITZ!Box VoIP Remote Code Execution

# SPDX-FileCopyrightText: 2017 Greenbone AG
# Some text descriptions might be excerpted from (a) referenced
# source(s), and are Copyright (C) by the respective right holder(s).
#
# SPDX-License-Identifier: GPL-2.0-only

CPE = "cpe:/o:avm:fritz%21_os";

if(description)
{
  script_oid("1.3.6.1.4.1.25623.1.0.108146");
  script_version("2025-09-10T05:38:24+0000");
  script_name("Multiple AVM FRITZ!Box VoIP Remote Code Execution");
  script_tag(name:"cvss_base", value:"10.0");
  script_tag(name:"cvss_base_vector", value:"AV:N/AC:L/Au:N/C:C/I:C/A:C");
  script_tag(name:"last_modification", value:"2025-09-10 05:38:24 +0000 (Wed, 10 Sep 2025)");
  script_tag(name:"creation_date", value:"2017-04-19 11:59:41 +0200 (Wed, 19 Apr 2017)");
  script_category(ACT_GATHER_INFO);
  script_family("General");
  script_copyright("Copyright (C) 2017 Greenbone AG");
  script_dependencies("gb_avm_fritz_box_consolidation.nasl");
  script_mandatory_keys("avm/fritz/model", "avm/fritz/firmware_version");

  script_xref(name:"URL", value:"https://www.heise.de/newsticker/meldung/Firmware-Status-von-AVM-Routern-checken-Kritisches-Sicherheitsloch-in-Fritzbox-Firmware-gestopft-3687437.html");
  script_xref(name:"URL", value:"https://avm.de/service/aktuelle-sicherheitshinweise/");

  script_tag(name:"vuldetect", value:"Check the firmware version.");

  script_tag(name:"solution", value:"Update the firmware to 6.83 or higher.");

  script_tag(name:"summary", value:"Several models of the AVM FRITZ!Box are vulnerable to a heap-based buffer overflow,
  which allows attackers to execute arbitrary code on the device.");

  script_tag(name:"affected", value:"AVM FRITZ!Box 7390, 7490 und 7580 with a firmware 6.80 or 6.81.");

  script_tag(name:"qod_type", value:"remote_banner");
  script_tag(name:"solution_type", value:"VendorFix");

  exit(0);
}

include("version_func.inc");
include("host_details.inc");

if( ! fw_version = get_app_version( cpe:CPE, nofork:TRUE ) ) exit( 0 );
if( ! model = get_kb_item( "avm/fritz/model" ) ) exit( 0 );

valid_models = make_list( "7390", "7490", "7580" );

foreach m( valid_models ) {
  if( egrep( string:model, pattern:'^' + m ) ) {
    vuln_model = TRUE;
    break;
  }
}

if( ! vuln_model ) exit( 0 );

patch = "6.83";
# Only 06.8x are vulnerable
if( fw_version !~ "^6\.8" ) exit( 99 );

if( version_is_less( version:fw_version, test_version:patch ) ) {
  report  = 'Model:              ' + model + '\n';
  report += 'Installed Firmware: ' + fw_version + '\n';
  report += 'Fixed Firmware:     ' + patch;
  security_message( port:0, data:report );
  exit( 0 );
}

exit( 99 );