fingerd buffer overflow

# SPDX-FileCopyrightText: 2005 Michel Arboi
# 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("1.3.6.1.4.1.25623.1.0.17141");
  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_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_xref(name:"URL", value:"http://www.securityfocus.com/bid/2");
  script_name("fingerd buffer overflow");
  script_category(ACT_DENIAL);
  script_copyright("Copyright (C) 2005 Michel Arboi");
  script_family("Denial of Service");
  script_dependencies("find_service.nasl", "find_service1.nasl", "find_service2.nasl");
  script_require_ports("Services/finger", 79);

  script_tag(name:"solution", value:"Disable the finger daemon, apply the latest patches from the
  vendor, or use a safer software.");

  script_tag(name:"summary", value:"The scanner was able to crash the remote finger daemon by sending a too long
  request.");

  script_tag(name:"impact", value:"This flaw is probably a buffer overflow and might be exploitable
  to run arbitrary code on this machine.");

  script_tag(name:"solution_type", value:"Mitigation");
  script_tag(name:"qod_type", value:"remote_probe");

  exit(0);
}

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

port = service_get_port(default:79, proto:"finger");

soc = open_sock_tcp(port);
if(!soc)
  exit(0);

send(socket:soc, data:crap(4096) + '\r\n');
r = recv(socket:soc, length:65535);
close(soc);

sleep(1);

soc = open_sock_tcp(port);
if(!soc){
  security_message(port:port);
  exit(0);
} else {
  close(soc);
}

if(!r) {
  report  = "The remote finger daemon abruptly closes the connection when it receives a too long request. It might be vulnerable to an exploitable buffer overflow. ";
  report += "Note that the scanner did not crash the service, so this might be a false positive. However, if the finger service is run through inetd (a very common configuration), ";
  report += "it is impossible to reliably test this kind of flaw.";
  security_message(port:port, data:report);
  exit(0);
}

exit(99);