The sys admin's (and the professor's) daily grind: Do-it-yourself antispam blacklists

Garbage Incinerator

Article from Issue 99/2009
Author(s): , Author(s):

At the Niederrhein University future admins implement spam defense mechanisms by attracting the attention of the Viagra Mafia. The results are pertinacious blacklists and expert knowledge of methods for combating the menace.

A project at Niederrhein University [1], Krefeld, Germany, prepares students for their working lives, teamwork, and the daily madness, part of which is the inflationary emergence of spam. Spam can be fought by the use of various methods, and one of them is the spam blacklist (SBL). Now students at the university are working on implementing and maintaining an SBL.

Following the idea of "Fight Spam with Spam," we deliberately set up IMAP and POP3 mail accounts that were not protected from spam. The accounts acted as honeypots to catch spam mail. To attract spammers, the students spread the honeypot email addresses as widely as they could. To do so, they ignored all the rules concerning responsible use of email addresses and published the addresses on websites in social networks; they also posted in test newsgroups such as de.test and visited the darkest corners of the web they could find.

It didn't take long to achieve satisfactory results: The accounts soon filled up with tons of spam. The students' assignment was to set up a system to determine the origin of the incoming messages as quickly as possible (by identifying the IP address of the sending server) and to add the spam to the blacklist for a defined period of time.

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