Using Internet Standards to Control the Cost of Spam
A standards-based attempt to control the cost of unsolicited
bulk electronic mail at the Greater Columbus Free-Net.
With the explosion of the number of Internet-connected
hosts and the unprecidented growth of the number of people using the
Internet, clear erosion on the 'Information Super Bike-Path' is
becoming apparent. One of the most visible problems for the Internet
is the issue of 'spam' -- unsolicited bulk electronic mail which is
generally of a commercial nature. It is possible to define patterns
with which we can identify spam and thus put into place measures which
will reduce the volume (and cost) of running electronic mail services,
without undermining legitimate use of such systems.
COPYRIGHT
This presentation and area are:
Copyright ©1997-8 by the Greater
Columbus Free-Net.
All rights reserved.
HISTORY
- 23 Jul 97 to the Ohio State University Security Working Group.
- 23 Oct 97, Network Security '97 birds-of-a-feather session.
- 12 May 98, SANS '98 peer-reviewed session
SUMMARY
The Greater Columbus Free-Net (GCFN.ORG) has become concerned about the
issue of unsolicited, unwelcome, unwanted, high-volume electronic
mail, which for the purposes of this discussion shall be called
"spam."
Spam is problematic for a number of reasons, the most important of
which is that the real cost of such traffic is carried by people
other than those who benefit from it. In terms of the GCFN.ORG
problem, by early June, 1997, spam had become such an incredible drain
on our staff time that, in order to guarantee project continuation,
some controlling measures had to be put into place. Our analysis of
many of the numerous spam complaints we've received determined that
there are patterns to at least the kinds of spam that users get upset
about. Our analysis seems to indicate that certain parts of the
published standards for e-mail communication were not being followed
in many spam incidents.
Thus, an effective method for controlling spam would be to enforce
standards compliance on incoming electronic mail. Using the Berkeley
sendmail package (version 8.8), we implemented two
standards-compliance checks against the SMTP (e-mail) delivery
transactions. The result: a drop in spam volume -- over a quarter
million attempts to deliver non-compliant mail were rejected -- with
exactly no legitimate messages being blocked over the
3-week examination period following our changes.
Following the initial successes of the sendmail defensive
measures, users experienced a second wave increase in spam volume.
Through the creation of an anti-spam filtering system that
users have direct control over resolved the staff
commitment and gave the users a sense of self-determination and
allowed them to re-take control of their electronic mail usage once
more.
The technical portion of this talk discusses the technology and
standards of electronic mail transmission, with a strong focus on
effective choke points that can be utilized to reduce
unsolicited, unwanted, unwelcome electronic mail. Specifically, we
consider run-time and compile-time options to reduce the cost of
running an electronic mail service within the context of the
sendmail v8.8 software and the procmail 3.11pre7
mail processor.
The policy portion of this talk discusses the current legal status of
electronic mail defense mechanisms, consideration of some of the
management issues involved in determining the cost that spam is
inducing on a system.
This material requires aproximately one-hour. It is written to the
interested site administrator or policy maker audience.
REFERENCES
- Spam Gift Catalog - Here
as a reminder that you shouldn't lose perspective when spam fighting.
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