QUOTE(michaelanglo @ May 29 2009, 07:42 AM)

I've seen the message from time to time. I don't think the To: matters but here is an example with Subject: present but all blanks IIRC Subject: missing is the same.
...
Changing this to Subject: none causes the message to go away.
...
These have "Sender:" rather than "From:" but I don't think that matters either.
Wow, thanks michaelanglo (I don't see the "Subject: present but all blanks", but that doesn't matter). Multiple weirdness - trying to replicate your broken example with current date (since these are, as dra007 pointed out 'way back then', reportable and wanting to see if there were any further clues/messages in the unreported spam dialog) produced
with no mailhosting set:
QUOTE
Please make sure this email IS spam:
From: ()
This disappears from the cancelled (US spelling be damned) report tracker but, sure enough, inserting a "From: nobody" (has to be something) makes the "Header data found in body" message go away - as seen (and "Subject:" absent):
http://www.spamcop.net/sc?id=z2946446101z7...d400f1849ab6c2zSo, missing "Subject:" can invoke the problem, missing "From:" can invoke the problem, at least without mailhosting, and (example still to be tabled) out-of-sequence (but not missing) "From:" "To:" and "Subject" headers are said to invoke it BUT, paradoxically, deleting them is said to make it go away. We need Xoxcatpl input/examples on that.
This will be of interest to the deputies, I'm fairly sure adding bogus data would be out of the question (especially since reports to the spamsource hosts are still generated) but the deputies would need to rule on that. Equally (which is to say IMO only) sure deleting data would be out of the question. Deputies (and engineering) will be especially interested if it turns out this problem has resurfaced/changed as a result of recent changes to the parser code (I don't know). That would indicate the regression testing was somewhat deficient - though, they would probably say, "in a non-critical way". Thing is, in the interests in not 'tempting' users WRT to breaches of the 'material changes' rule it would be better if it didn't happen.
So, as far as I am concerned (for the benefit of others reading), waiting to see if Xoxcatpl (or anyone else) has further input before 'burdening'

the deputies with these observations. In the meantime, remember dra007's 'bottom line' (earlier in this topic). They are still reportable, without alteration. If you want to alert hosts of 'spamvertizers', make a
Manual Report. Just use the parser input form (with the spam URL only) to get the abuse address - if that includes 'devnull' it may indicate it would be imprudent to send a report.
[edit - just to add that the non-printable character in michaelangelo's example is the 'concatenate' (hex 1C, in the fake "Message-Id:" header) - there often is one in this sort of weirdness it seems - but removing it does nothing to the parse AFAICT]