Thursday, October 06, 2005

Spam, DOS, and cell phones

I've always been surprised at the lack of spam on cell phone SMS. For the most part, everyone who has the ability to receive short messages on their phone has an email address, and there's no fundamental reason that spammers couldn't send messages to lists of cell phone numbers. I assume that the phone companies employ spam filters, so at least long messages and messages that contain HTML get rejected. But maybe the spammers have decided that short messages to cell phones doesn't pay in terms of money received (for one thing, there's no connection between reading the message and getting on a web browser to give the spammers your money). The story linked from the title raises another issue, which is the launching of denial of service (DOS) attacks on cell phone networks. By sending messages from the internet fast enough (easily achievable with a single computer), voice traffic can be halted -- a result of the dual use of network control channels (the ones used to set up voice calls) to also carry the short messages (because their bandwidth requirements are expected to be low).

The take-home message, as always, is that a cell phone is a luxury -- there's no substitute for a land line, switched network telephone in an emergency.


  1. I went to India in the summer and was surprised at the amount of spam sent to my father's cell phone. It seems that DoS is a common event in India during holiday events especially Valentines Day, New Year, election campaign etc. At present, I do not have any news article to cite. But, will come back when I get hold of one.

  2. Yes the article mentions that disruptions have occurred overseas "by accident". BTW, I've fixed the link so it now should work without NYT registration.