Posted on by Silverdog

De-Obfuscating CloudFlare’s protected emails with Perl!

Doing some scraping with perl, I got a page served by CloudFlare that obfuscate emails to avoid bots collecting this data. Of course, What I need? yes, the emails…

This measures just raise the difficulty to get the information but not make it impossible.

Googling a little I found a 2 years old post from Jesse Li who explains the obfuscation process and solve this with JavaScript.

function hex_at(str, index) {
  var r = str.substr(index, 2);
  return parseInt(r, 16);
}
function decrypt(ciphertext) {
  var output = "";
  var key = hex_at(ciphertext, 0);
  for(var i = 2; i < ciphertext.length; i += 2) {
    var plaintext = hex_at(ciphertext, i) ^ key;
    output += String.fromCharCode(plaintext);
  }
  output = decodeURIComponent(escape(output));
  return output;
}

With a little of programming translation I did it with Perl.

#!/usr/bin/perl -w
my $encodedEmail = $ARGV[0];

sub unDecode {
    return my $val = sprintf("%d", hex(substr $_[0], $_[1], 2));
}

sub deCrypt {
    my $email = "";
    my $key = unDecode($_[0], 0);
        for ( my $i = 2; $i < length $_[0] ; $i += 2) {
            my $a = unDecode($_[0], $i);
            my $char = chr(int($a) ^ int($key));
            $email = $email . $char;
        }
    return $email;
}
print deCrypt($encodedEmail) . "\n";

At this point I just integrated to me main scraper program and VOILA!

This code is on my github