Samba 'fd_open_atomic infinite loop' DoS Vulnerability (CVE-2017-9461)

# 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:/a:samba:samba";

if(description)
{
  script_oid("1.3.6.1.4.1.25623.1.0.811083");
  script_version("2025-09-17T05:39:26+0000");
  script_cve_id("CVE-2017-9461");
  script_tag(name:"cvss_base", value:"6.8");
  script_tag(name:"cvss_base_vector", value:"AV:N/AC:L/Au:S/C:N/I:N/A:C");
  script_tag(name:"last_modification", value:"2025-09-17 05:39:26 +0000 (Wed, 17 Sep 2025)");
  script_tag(name:"severity_vector", value:"CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H");
  script_tag(name:"severity_origin", value:"NVD");
  script_tag(name:"severity_date", value:"2019-10-03 00:03:00 +0000 (Thu, 03 Oct 2019)");
  script_tag(name:"creation_date", value:"2017-06-07 17:35:53 +0530 (Wed, 07 Jun 2017)");
  script_name("Samba 'fd_open_atomic infinite loop' DoS Vulnerability (CVE-2017-9461)");
  script_category(ACT_GATHER_INFO);
  script_copyright("Copyright (C) 2017 Greenbone AG");
  script_family("Denial of Service");
  script_dependencies("smb_nativelanman.nasl", "gb_samba_detect.nasl");
  script_mandatory_keys("samba/smb_or_ssh/detected");

  script_xref(name:"URL", value:"https://bugzilla.samba.org/show_bug.cgi?id=12572");
  script_xref(name:"URL", value:"https://git.samba.org/?p=samba.git;a=commit;h=10c3e3923022485c720f322ca4f0aca5d7501310");

  script_tag(name:"summary", value:"Samba is prone to a denial of service (DoS) vulnerability.");

  script_tag(name:"vuldetect", value:"Checks if a vulnerable version is present on the target host.");

  script_tag(name:"insight", value:"The flaw exists due to error in smbd
  which enters infinite loop when trying to open an invalid symlink with O_CREAT.");

  script_tag(name:"impact", value:"Successfully exploiting this issue will allow
  remote attackers to conduct a denial-of-service condition(infinite loop with
  high CPU usage and memory consumption).");

  script_tag(name:"affected", value:"Samba versions before 4.4.10 and 4.5.x
  before 4.5.6");

  script_tag(name:"solution", value:"Upgrade to Samba 4.4.10 or 4.5.6 or later.");

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

  exit(0);
}

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

if( isnull( port = get_app_port( cpe:CPE ) ) )
  exit( 0 );

if( ! infos = get_app_version_and_location( cpe:CPE, port:port, exit_no_version:TRUE ) )
  exit( 0 );

vers = infos["version"];
loc = infos["location"];

if(version_is_less(version:vers, test_version:"4.4.10")){
  fix = "4.4.10";
}

else if(vers =~ "^4\.5\." && version_is_less(version:vers, test_version:"4.5.6")){
  fix = "4.5.6";
}

if(fix){
  report = report_fixed_ver( installed_version:vers, fixed_version:fix, install_path:loc );
  security_message( data:report, port:port);
  exit(0);
}

exit(99);