here some suggestions to improve your code

use strict;
use warnings;
use Data::Dumper qw(Dumper);



my @sites=qw/
              www.yahoo.com
              www.google.com
              www.comcast.com
            /;
my @bad_log;

LINE:
while (my $line = <DATA>) {
  my $www = (split / /,$line)[5];   
  foreach my $site (@sites) {
    next if $site eq "";
    if ( $www =~ /\Q$site/ ) {
      push @bad_log, $line;
      next LINE;
    }
  }
}

print Dumper \@bad_log;

__DATA__
X456 TV-yes DB-no 123.12.23.45 dealio3 www.google.com-------- FX-yes d
+53 Y-03
X123 TV-yes DB-yes 34.154.43.21 dealio1 www.ask.com-------- FX-no d01 
+Y-03
X412 TV-no DB-no 192.365.25.23 rayovac2 www.microsoft.com--- FX-yes d1
+3 Y-07
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