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Showing posts from June, 2007

Pretty Darn Fancy: Even More Fancy Spam

Looks like the PDF wave of spam is proceeding with a totally different tack. Sorin Mustaca sent me a PDF file that was attached to a pump and dump spam. Unlike the previous incarnation of PDF spams, this one looks a lot like a 'classic' image-spam.



It's some text (which has been misaligned to fool OCR systems), but there's a little twist. Zooming in on a portion of the spam shows that the letters are actually made up of many different colors (a look inside the PDF it's actually an image.



I assume that the colors and the font misalignement is all there to make it difficult to OCR the text (and wrapping it in a PDF will slow down some filters).

Extracting the image and passing it through gocr gave the following result:

_ Ti_ I_ F_ _ Clih! %
ogx.

%_ % _c. (sR%)
t0.42 N %x

g0 _j_ __ h_ climb mis _k
d% % %g g nle_ Frj%.
_irgs__Dw_s _ rei_ � a
f%%d __. n_ia une jg gtill
oo_i_. Ib _ _ _ _ _ _ 90I
Tgdyl

And a run through tesseract resulted in:

9{Eg Takes I:-west.tY`S Far Gawd Climb! …

Pretty Darn Fancy: Stock spammers using PDF files

Joe Chongq sent me a fascinating spam that is the first I've seen that's using a PDF file to send its information. I've long predicted that we'll see a wave of complex formats used for spam as broadband penetration increases and sending large spams becomes possible.

This particular spam has a couple of interesting attributes:

1. The PDF file itself is a really nicely formatted report about a particular stock that's being pumped'n'dumped.

2. The file name of the PDF was chosen to entice the user further by using their first name. In this case it was called joe_report.pdf.

3. The PDF is compressed using the standard PDF 'Flate' algorithm and totals 84,398 bytes. That's fairly large, but we've certainly seen image spams that were larger. Use of compression here means that a spam filter that's not aware of PDF formats would be unable to read the message content.

Here's what the actual PDF looks like (click for a larger view):

.

Escaping comma and space in GNU Make

Sometimes you need to hide a comma or a space from GNU Make's parser because GNU Make might strip it (if it's a space) or interpret it as an argument separator (for example, in a function invocation).

First the problem. If you wanted to change every , into a ; in a string in GNU Make you'd probably head for the $(subst) function and do the following:

$(subst ,,;,$(string))

See the problem? The argument separator for functions in GNU Make is , and hence the first , (the search text) is considered to be separator. Hence the search text in the above is actually the empty string, the replacement text is also the empty string and the ;, is just preprended to whatever is in $(string).

A similar problem occurs with spaces. Suppose you want to replace all spaces with ; in a string. You get a similar problem with $(subst), this time because the leading space is stripped:

$(subst ,;,$(string))

That extra space isn't an argument it's just extraneous whitespace and h…

POPFile v0.22.5 Released

Here are the details:

Welcome to POPFile v0.22.5

This version is a bug fix and minor feature release that's been over a
year in the making (mostly due to me being preoccupied by other
things).


NOMINATING POPFILE FOR AN AWARD

SourceForge has announced their 'Community Choice Awards' for 2007 and
is looking for nominations. If you feel that POPFile deserves such an
honour please visit the following link and nominate POPFile in the
'Best Project for Communications' category. POPFile requires multiple
nominations (i.e. as many people as possible) to get into the list of
finalists.

http://sourceforge.net/awards/cca/nomination.php?group_id=63137

Thanks!


WHAT'S CHANGED SINCE v0.22.4

1. POPFile now defaults to using SQLite2 (the Windows installer will
convert existing installations to use SQLite2).

2. Various improvements to the handling of Japanese messages and
improvements for the 'Nihongo' environment:

Performance enhancement for converting character encoding by