mirror of
https://github.com/BlackLight/Snort_AIPreproc.git
synced 2024-11-24 04:35:11 +01:00
132 lines
2.7 KiB
Perl
Executable file
132 lines
2.7 KiB
Perl
Executable file
#!/usr/bin/perl
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use strict;
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use warnings;
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use MIME::Base64;
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use Env qw(QUERY_STRING DOCUMENT_ROOT);
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sub url_decode {
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my $str = shift;
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$str =~ s/%([A-Fa-f0-9]{2})/pack('C', hex($1))/seg;;
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return $str;
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}
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sub print_pcap_header {
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my $out = shift;
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# pcap magic_number
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print $out pack ( 'L', 0xa1b2c3d4 );
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# pcap version_major
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print $out pack ( 'S', 0x2 );
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# pcap version_minor
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print $out pack ( 'S', 0x4 );
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# pcap thiszone
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print $out pack ( 'l', 0x0 );
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# pcap sigfigs
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print $out pack ( 'L', 0x0 );
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# pcap snaplen
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print $out pack ( 'L', 0xffff );
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# pcap network
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print $out pack ( 'L', 0x1 );
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}
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sub print_packet {
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my ( $out, $packet ) = @_;
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# ts_sec
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print $out pack ( 'L', $packet->{'time'} );
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# ts_usec
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print $out pack ( 'L', 0x0 );
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my $pkt_data = decode_base64 ( url_decode ( $packet->{'content'} ));
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my $hex = unpack ( 'H*', $pkt_data );
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my @pairs = $hex =~ /([a-fA-F0-9]{2})/g;
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# If this is not an IP packet, trust what the client has told you as packet length
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if (( $pairs[0] ne '45' && $pairs[1] ne '00' ) || ( @pairs < 5 ))
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{
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# incl_len
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print $out pack ( 'L', $packet->{'length'} + 12 );
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# orig_len
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print $out pack ( 'L', $packet->{'length'} + 12 );
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} else {
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# Otherwise, the length of the packet is the one specified in the IP header
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my $length = hex ( $pairs[2].$pairs[3] );
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# If the lengths differ (IP length and actual length of the stream received), pad
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# the end of the packet with some 0's so that its length matches the one
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# specified in the IP header
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if ( $length > ( length ( $hex ) / 2 ))
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{
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my $pad_size = $length - ( length ( $hex ) / 2 );
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$hex .= '00' for ( 0..$pad_size-1 );
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$pkt_data = pack ( 'H*', $hex );
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}
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# Add the length of a pseudo-ethernet header
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$length += 14;
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# incl_len
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print $out pack ( 'L', $length );
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# orig_len
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print $out pack ( 'L', $length );
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}
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# pseudo ethernet header
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print $out pack ( 'H*', 0 x24 );
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# ethernet type (IP)
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print $out pack ( 'S', 0x8 );
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# packet content
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print $out $pkt_data;
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}
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$QUERY_STRING =~ /packets=([0-9]+)/;
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my $packets_num = $1;
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my %packets = ();
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for ( my $i=0; $i < $packets_num; $i++ )
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{
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$QUERY_STRING =~ /packet_len$i=([0-9]+)/;
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my $length = $1;
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$QUERY_STRING =~ /time$i=([0-9]+)/;
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my $time = $1;
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$QUERY_STRING =~ /packet$i=(.+?)(&|$)/;
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my $content = $1;
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$packets{$i} = {
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'length' => $length,
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'time' => $time,
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'content' => $content
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};
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}
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print "Content-Type: application/pcap\n\n";
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# open my $out, "> $DOCUMENT_ROOT/out.pcap";
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open my $out, ">&STDOUT";
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binmode $out;
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print_pcap_header $out;
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for ( my $i=0; $i < $packets_num; $i++ )
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{
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print_packet $out, $packets{$i};
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}
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close $out;
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# print "Content-Type: text/html\\n\\n";
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# print "<meta http-equiv=\\"refresh\\" content=\\"0;url=/out.pcap\\">\\n";
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