#!/usr/bin/perl
 
 $exist = `iptables -nL INPUT | grep SSH_KNOCK`;
 
 if ($exist ne '')
 {
         `iptables -D INPUT -m state --state NEW -p tcp -j SSH_KNOCK`;
         `iptables -F SSH_KNOCK`;
         `iptables -X SSH_KNOCK`;
         print "[+] Port knocking rules deactivated.\n";
 }
 else
 {
         print "[-] Port knocking rules have been already deactivated.\n";
 }

#!/usr/bin/perl
 
 if (@ARGV < 1) {         
         print "Usage:\r\n";         
         print "Specify passkey! \r\n\r\n";
         exit(); 
 }   
 $port = 0;  
 srand($ARGV[0]);  
 $exist = `iptables -nL INPUT | grep SSH_KNOCK`;  
 if ($exist ne '') {   
         `iptables -F SSH_KNOCK`; 
 } else { 
         `iptables -N SSH_KNOCK`;
         `iptables -I INPUT -m state --state NEW -p tcp -j SSH_KNOCK`; 
 }  
 `iptables -A SSH_KNOCK -p tcp --dport 22 -m recent --rcheck --name SSHK -j ACCEPT`;
 `iptables -A SSH_KNOCK -m recent --rcheck --name SSHK -j RETURN`; 
 # A potential bug here - not checking if there are successive random generated port numbers 
 for ($i=0; $i<5; $i++) {         
         $port = int(rand(40000) + 1024);
         $prev_port = $port - 1;
         $next_port = $port + 1; 
         `iptables -A SSH_KNOCK -p tcp --dport $port -m recent --name SSHK --set -j DROP`;         
         `iptables -A SSH_KNOCK -p tcp --dport $prev_port -m recent --name SSHK --remove -j DROP`;         
         `iptables -A SSH_KNOCK -p tcp --dport $next_port -m recent --name SSHK --remove -j DROP`; 
 }
 `iptables -A SSH_KNOCK -p tcp --dport 22 -j DROP`;  
 print "[+] Port knocking rules activated.\n"; 

#!/usr/bin/perl
 
 use IO::Socket;
 
 if (@ARGV < 2) {         
         print "Usage:\r\n";         
         print "Specify host !\r\n";
         print "Specify passkey! \r\n\r\n";
         exit(); 
 }
 $serv = $ARGV[0];
 $serv =~ s/http:\/\///ge;
 $port = 0;
 srand($ARGV[1]);
 for ($i=0; $i<5; $i++) {
         $port = int(rand(40000)+1024);
         $sock = IO::Socket::INET->new(Proto=>"tcp", PeerAddr=>"$serv", PeerPort=>"$port", Timeout=>"1");
         close($sock);
 }
 
 print "[+] Port knocking finished.\n";
 
 $sock = IO::Socket::INET->new(Proto=>"tcp", PeerAddr=>"$serv", PeerPort=>"22")
 or die "[-] Port 22 - SSH NOT open.\n";
 close($sock);
 print "[+] Post 22 - SSH is now open.\n";