Educause Security Discussion mailing list archives

Re: Image SPAM Increase?


From: Mark Borrie <mark.borrie () OTAGO AC NZ>
Date: Thu, 20 Apr 2006 09:00:59 +1200

I started seeing these spam a few weeks ago and then they stopped
getting through.

We have used PureMessage for a couple of years and updates to rules
are occur potentially every 5 minutes. We don't do any rule tuning.

The main reason I think that these messages are no longer getting
through is the blocker service that is part of PureMessage. A database
of IPs known to send spam is maintained and we no longer accept
smtp connections from these systems. Every IP I have checked to date
appears to be a home/broadband system, i.e. part of a botnet.
Legitimate attempts to send mail receive appropriate error messages
so that we can sort out the issue.

Mark

On 19 Apr 2006 at 12:08, Gary Flynn wrote:


Over the past few weeks we've seen a slow increase in SPAM messages
related to stock market advice. We're starting to see regular reports
from our users of this new ( for us ) activity. The messages are
composed:

1) entirely of images

--or--

2) Images prepended with gibberish

Messages have been received from computers around the
world and sources don't seem to repeat.

Our email system is assigning them junkmail scores too
low to keep them out of regular mailboxes.

Anyone else seeing these? If not, do you know what is
keeping you from seeing them? Anti-spam device or
product? ORB list? SPF? Custom filter?

How would any SPAM filter be able to deal with a message
made up entirely of an image and sent from varying
computers? Is it safe to assume there are no filters
that have OCR capabilities :)

What actions do you take and/or what recommendations do
you offer to users when faced with an increase in
unfilterable messages?

thanks,

--
Gary Flynn
Security Engineer
James Madison University
www.jmu.edu/computing/security




--
Mark Borrie
Information Security Manager,
Information Technology Services, University of Otago,
Dunedin, N.Z.
Ph +64 3 479-8395, Fax +64 3 479-5080, Mobile +64 27 609-6409

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