#!/usr/bin/perl -Tw
# Jon Hart <warchild@spoofed.org>
#
# Simple perl script to decode a string or file
# from hex to its ascii equivalent.
#
# Especially useful for decoding web attacks, i.e.:
#
# http://somesite/%2e%2e%2f%2e%2e%2f%2e%2e%2f%2e%2e%2f%2e%2e%2f%2e%2e%2f%57%49%4e%44%4f%57%53%2f%73%79%73%74%65%6d%33%32%2f%63%6d%64%2e%65%78%65%2b%64%69%72%2b%63%3a
#
# is actually...
#
# http://somesite/../../../../../../WINDOWS/system32/cmd.exe+dir+c:
#
use strict;
if ($ARGV[0]) {
   my $file = $ARGV[0];
   open(FILE, "< $file") or die "Couldn't open $file: $!\n";
   while (<FILE>) {
      decode($_);
   }
   close(FILE);
} else {
   while (<>) {
      decode($_);
   }
}
sub decode {
   my $string = shift;
   chomp($string);
   map { print(chr(hex("$_"))) } split(/\%/, $string);
   print("\n");
}