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#!/usr/bin/env perl
use strict;
use warnings;
BEGIN { $SIG{INT} = $SIG{TERM} = sub { exit 0 } }
use Getopt::Long;
use Pod::Usage;
GetOptions (
'help|?' => sub { pod2usage(2) },
'ip=s' => \my $target_ip,
);
# validate required args are given
die "Missing --ip parameter, try --help\n" unless $target_ip;
use Net::Address::IP::Local;
use IO::Socket::INET;
my $local_ip = Net::Address::IP::Local->public;
# find a random free port by opening a socket using the protocol
my $local_port = do {
my $socket = IO::Socket::INET->new(Proto => 'tcp', LocalAddr => $local_ip);
my $socket_port = $socket->sockport();
$socket->close;
$socket_port;
};
use List::Util 'shuffle';
my %port_directory;
open my $port_file, '<', 'data/nmap-services.txt'
or die "Error reading data/nmap-services.txt $!\n";
while (<$port_file>)
{
next if /^#/; # skip comments
chomp;
my ($name, $number_protocol, $probability, $comments) = split /\t/;
my ($port, $proto) = split /\//, $number_protocol;
$port_directory{$number_protocol} = {
port => $port,
proto => $proto,
name => $name,
probability => $probability,
comments => $comments,
};
}
my @ports = shuffle do {
map { $port_directory{$_}->{port} }
grep { $port_directory{$_}->{name} !~ /^unknown$/
&& $port_directory{$_}->{proto} eq 'tcp' } keys %port_directory;
};
use Net::Pcap;
use POSIX qw/WNOHANG ceil/;
# apportion the ports to scan between processes
my $procs = 50;
my $batch_size = ceil(@ports / $procs);
my %total_ports = map { $_ => 'filtered' } @ports; # for reporting
my @child_pids;
for (1..$procs)
{
my @ports_to_scan = splice @ports, 0, $batch_size;
my $parent = fork;
die "unable to fork!\n" unless defined ($parent);
if ($parent)
{
push(@child_pids, $parent);
next;
}
# child waits until the parent signals to continue
my $continue = 0;
local $SIG{CONT} = sub { $continue = 1};
until ($continue) {}
for my $target_port (@ports_to_scan)
{
sleep(1);
send_packet($target_port);
}
exit 0; # exit child
}
# setup parent packet capture
my $device_name = pcap_lookupdev(\my $err);
pcap_lookupnet($device_name, \my $net, \my $mask, \$err);
my $pcap = pcap_open_live($device_name, 1024, 0, 1000, \$err);
pcap_compile(
$pcap,
\my $filter,
"(src net $target_ip) && (dst port $local_port)",
0,
$mask
);
pcap_setfilter($pcap,$filter);
# signal the child pids to start sending
kill CONT => $_ for @child_pids;
until (waitpid(-1, WNOHANG) == -1) # until all children exit
{
my $packet_capture = pcap_next_ex($pcap,\my %header,\my $packet);
if($packet_capture == 1)
{
read_packet($packet);
}
elsif ($packet_capture == -1)
{
warn "libpcap errored while reading a packet\n";
}
}
use Net::RawIP;
sub send_packet
{
my ($target_port) = @_;
Net::RawIP->new({ ip => {
saddr => $local_ip,
daddr => $target_ip,
},
tcp => {
source => $local_port,
dest => $target_port,
syn => 1,
},
})->send;
}
use NetPacket::Ethernet;
use NetPacket::IP;
use NetPacket::TCP;
sub read_packet
{
my ($raw_data) = @_;
my $ip_data = NetPacket::Ethernet::strip($raw_data);
my $ip_packet = NetPacket::IP->decode($ip_data);
# is it TCP
if ($ip_packet->{proto} == 6)
{
my $tcp = NetPacket::TCP->decode(NetPacket::IP::strip($ip_data));
my $port = $tcp->{src_port};
my $port_name = exists $port_directory{"$port/tcp"}
? $port_directory{"$port/tcp"}->{name}
: '';
if ($tcp->{flags} & SYN)
{
printf " %5d %-20s %-20s\n", $port, 'open', $port_name;
$total_ports{$port} = 'open';
}
elsif ($tcp->{flags} & RST)
{
printf " %5d %-20s %-20s\n", $port, 'closed', $port_name;
$total_ports{$port} = 'closed';
}
}
}
printf "\n %d ports scanned, %d filtered, %d closed, %d open\n",
scalar(keys %total_ports),
scalar(grep { $total_ports{$_} eq 'filtered' } keys %total_ports),
scalar(grep { $total_ports{$_} eq 'closed' } keys %total_ports),
scalar(grep { $total_ports{$_} eq 'open' } keys %total_ports);
END { pcap_close($pcap) if $pcap }
__END__
=head1 NAME
port_scanner - a concurrent randomized tcp/udp port scanner written in Perl
=head1 SYNOPSIS
port_scanner [options]
Options:
--ip, -i ip address to scan e.g. 10.30.1.52
--help, -h display this help text
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