WargamesMY CTF 2018: You Math Bro?

Challenge required to answer 30 questions within 40 seconds and clearly requires some form of automation.

Program also throws occasional extra text, make accommodations for it.

print("y u eval bro");exit();

1	print("y u eval bro");exit();

Let’s write a script.

Solution:

#!/usr/bin/perl

use IO::Socket::INET;
use bigint;
$| = 1;

my ($socket,$client_socket);

$socket =  IO::Socket::INET->new (
  PeerAddr => "206.189.93.101",
  PeerPort => "4343",
  Type     => SOCK_STREAM,
  Proto => "tcp",
) or die "ERROR no socket created :( $!\n";
#Initial keyword expected by server to begin
my $start = "start";
print $socket $start . "\n";

my $html = "";
my $buffer = "";

while ( my $line = <$socket> ) {
  print $line;
  chomp $line;
#Replace 'x' with '*' for multiplication
  $line =~ tr/x/*/;
#Regex capture expression to evaluate
  if ( $line =~ /(\w.*\s\[.*])\s(\d.*\d)(.*)$/){
     my $result = eval($2);
     print $socket $result . "\n";
  }
}

#!/usr/bin/perl

use IO::Socket::INET;

use bigint;

$| = 1;

my ($socket,$client_socket);

$socket = IO::Socket::INET->new (

PeerAddr => "206.189.93.101",

PeerPort => "4343",

Type => SOCK_STREAM,

Proto => "tcp",

) or die "ERROR no socket created :( $!\n";

#Initial keyword expected by server to begin

my $start = "start";

print $socket $start . "\n";

my $html = "";

my $buffer = "";

while ( my $line = <$socket> ) {

print $line;

chomp $line;

#Replace 'x' with '*' for multiplication

$line =~ tr/x/*/;

#Regex capture expression to evaluate

if ( $line =~ /(\w.*\s\[.*])\s(\d.*\d)(.*)$/){

my $result = eval($2);

print $socket $result . "\n";

}

Flag : wgmy{d0_you_ev3n_m4th_br0}

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WargamesMY CTF 2018: You Math Bro?

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