Peculiar new type of spam, what gives?

[LeeRyder]

The past week has seen a very peculiar type of spam surfacing at my gmail (my dedicated spam catcher account) email.

no links or ad of any type. No attachments, nada. Simply a one word subject and a one word text inside the email. get 2 or 3 an hour of these... always forged info (addy) etc... so it is spam..but.???

only one clue is this: Each email has a text inside (perhaps it's gmail's inputting it?) that says "7 bit encoding".

anyone have a clue?

One of the reports is as pasted directly for examination and clarification:

X-Gmail-Received: fd70f07879743db307e517a77c0931aaae727a28

Delivered-To: x

Received: by 10.64.183.7 with SMTP id g7cs30093qbf;

Sun, 24 Sep 2006 03:14:26 -0700 (PDT)

Received: by 10.48.210.20 with SMTP id i20mr88891nfg;

Sun, 24 Sep 2006 03:14:25 -0700 (PDT)

Return-Path: <pzrys4ba[at]esinet.net>

Received: from cable243a092.usuarios.retecal.es (cable243a092.usuarios.retecal.es [212.183.243.92])

by mx.gmail.com with SMTP id l32si2686345nfa.2006.09.24.03.14.24;

Sun, 24 Sep 2006 03:14:25 -0700 (PDT)

Received-SPF: fail (gmail.com: domain of pzrys4ba[at]esinet.net does not designate 212.183.243.92 as permitted sender)

Message-Id: <4516___________________________________DDED[at]mx.gmail.com>

From: pzrys4ba[at]esinet.net

To: x

Subject: slow

Date: Sun, 24 Sep 2006 05:14:23 -0600

Content-Type: text/plain;

Content-Transfer-Encoding: 7Bit

goes

[bobbear]

212.183.243.92 is a Spanish cable user, so my guess would be it's just a misconfigured botnet zombie.

The '7-bit encoding' simply means that the data is all represented as short lines of US-ASCII data, i.e. unencoded, with no high end 8-bit ASCII characters.