Re: Spam using email on website

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On Tue, 7 Nov 2006 13:14:54 -0600 (CST), "Richard Lynch" wrote:

> The Bad Guys are probably cramming your $subject and $from data with
> an ENTIRE eamil, so your mail() function is, in effect, and Open
> Relay.  (That's very very very bad.)
> 
> Example:
> Normal Input
> $subject = "Hi!";
> 
> Bad Guy Input
> $subject = "Hi!\r\nCc: victim1@xxxxxxxxxxx\r\nvictim2@example.com";
> 
> If you do:
> mail($to, $subject, $body);
> 
> then you are letting THEM control the headers of your email, which
> lets them splice in 1000 recipients to their junk.

   Have you actually tried this? I set up a dummy
sendmail program that logs its input to a file,
and it turned out that PHP's mail() function
converts control characters to white space.

   More specifically, it performed the following
conversions (PHP 5.0.2 on Windows 98SE):

  To: and Subject:
  ----------------

  \x00       ->  Terminates string.
  \x01-\x1f  ->  Replaced by \x20.
  \x20-\x7e  ->  Passed through.
  \x7f       ->  Replaced by \x20.
  \x80       ->  Passed through.
  \x81       ->  Replaced by \x20.
  \x82-\x8c  ->  Passed through.
  \x8d       ->  Replaced by \x20.
  \x8e       ->  Passed through.
  \x8f-\x90  ->  Replaced by \x20.
  \x91-\x9c  ->  Passed through.
  \x9d       ->  Replaced by \x20.
  \x9e-\xff  ->  Passed through.

  Body:
  -----
  \x00       ->  Terminates string.
  \x01-\xff  ->  Passed through.


  --nfe

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