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30 Jan 2013
Last week I blogged about the way that lots of otherwise legitimate companies leak e-mail addresses to spammers. Here's a few more thoughts.
One person asked how I knew that these were leaks, and not dictionary attacks, since the addresses I use are fairly obvious, the name of an often well known company @ my domain. It's a reasonable question, but the answer is simple: the spam comes to addresses I've given to the companies, not to addresses I haven't. There's a trickle of spam to truly made up addresses, but they're easy to recognize.
Another perhaps surprising fact is that leaks tend to be small scale. For example, a friend noted that Aeroplan (Air Canada's spun off frequent flyer program) had leaked his address, but they haven't leaked mine, even even though we've both been members for over a decade. I've been trying to think of mechanisms that would lead to small leaks, and it's not pretty. Database security failures tend to be all or nothing, so although one can imagine a situation where the bad guys started downloading all of the email addresses and the connection failed, that doesn't explain multiple small leaks. But if I were a crooked employee at an ESP, spammers paid me for known good addresses, and I figured a level that would stay under the radar, well then, ...
It would be very interesting to track the ESPs used by firms whose lists have leaked. As far as I know, nobody's done that yet.
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