How to automate a DoS attack using the Post Office

Alt-revenge FAQ

By John Leyden, 14th April 2003

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Fancy taking revenge on someone you don't like by deluging someone with junk mail?

A little bit of knowledge can go a long way. Thanks to the increased readiness of companies to send out brochures and magazines to anyone who bothers to register online, the US Postal Service can become the agent of denial of service attacks.

This much is well known, but a recent paper by security researchers Simon Byers, Aviel Rubin and Dave Kormann demonstrates how to automate this attack.

If you type the following search string into Google -- "request catalogue name address city state zip" -- you'll get links to over thousands of Web forms where you can type in your information and receive a catalogue in the mail.

It'd be a tedious business to fill out many forms.

But anyone with a modest amount of programming skills, and a target's snail mail address, can automate the attack and deluge their victims with junk mail.

Last December, self-styled "spam king" Alan Ralsky let slip his snail-mail address. Internet activists seized on this information to deluge him with unwanted snail mail.

Within weeks he was getting hundreds of pounds of junk mail per day and was unable to find his real mail amongst the deluge.

A pleasantly ironic attack, made all the more satisfying by Ralsky's outraged reaction.

That attack took the collective effort of many thousands but automating the attack leaves us all vulnerable.

Noted security and encryption guru Bruce Schneier believes there is no easy defence against the attack.

"Companies want to make it easy for someone to request a catalogue. If the attacker used an anonymous connection to launch his attack -open wireless networks would be a good choice - I don't see how he would ever get caught," Schneier observes.

"Even worse, it could take years for the victim to get his name off all of the mailing lists," he adds.

Individual catalogue companies can protect themselves by blocking automated signups (inserting a step that a person can easily do, but a machine can't). But it only takes a limited percentage to omit this check for the attack to work.

Schneier isn't convinced this will happen.

"The attack works in aggregate; each individual catalogue mailer only participates to a small degree. There would have to be a lot of fraud for it to be worth the money for a single catalogue mailer to install the countermeasure," he writes.

Schneier concludes that as old physical process is moved onto the Internet such attacks are likely to become more prevalent.

Which isn't nice. ®