Jul 052014

Ever had email messages bounce back to you when you didn’t sent them in the first place?

Spoofing - pretending to be someone elseFrom time to time you may receive emails that appear to be notifications that an email you have sent could not be delivered. You may quite possibly receive several of these in a short space of time. This is a rather puzzling and disturbing phenomenon. Your first reaction is, quite possibly, to think that your email has been hacked and that someone is sending messages from your account. It is definitely worth changing your email password just to make sure that the account is still secure. If you can’t get into it because the password has been changed then you are in a spot of bother and you will need to contact your email provider (Gmail, or Hotmail, for instance, or your own internet provider if you use their mail servers).

Another possibility, though, is that your account is still intact and that what has happened is that someone is sending out emails from somewhere else and pretending that they came from you by changing the “from” details in the header of the email. This is called “spoofing”. They have “spoofed” your email address.

How can this happen? It could be that someone that you know has had their email hacked. Your email address has been stolen from that person’s email. The hacker then sends out emails to the email addresses found in the account, spoofing the sender’s name by taking one of the addresses found in the account (in this case, yours).

If the hacker steals, say, 50 addresses, and sends out emails to all of them then 10 may bounce. Those bounces will come to you and you will wonder what’s happening. The phenomenon of receiving bounces in this way is known as “backscatter“. So, “backscatter” is a by-product of someone “spoofing” your email address.

This is not the only way that it can occur. You will send your email address to many people over time. If you’ve created an account on a website, for instance, and given your email address (possibly as the username for that website) then your email address can be stolen if that website is hacked.

What can you do about it? There’s no way that you can actually prevent it from happening. After all, you don’t have any control over the many individuals and organisations that have your email address – legitimately or otherwise.

No SpamThere are some things you can do, however, to mitigate the problem. To begin with, register a “disposable” email account with someone (Gmail or Hotmail, for instance) and use that email address for unimportant logins that you could afford to lose. Then, if that account starts getting overwhelmed with backscatter (or, indeed, other forms of spam), you can just stop using it.

If you have your own website, it is a good idea to publish a contact email address on the website that is disposable. The email address I publish on my website is only used on the website. If I start getting inundated with spam to that address (including backscatter), I’ll simply change it for another one and not check for email addressed to the older one any more.

Abine - Masking Email AddressAnother thing you can do is to use the services of a site such as DoNotTrackMe. Using the email aspect of that service you can use a unique, disposable, email address when signing up for an online account. Email to that address is forwarded to you and the sender never knows your real address. If you start getting spammed or get backscatter you simply stop the emails to that address from being forwarded to your real address. I’ve been testing this for a month or two and it seems to work. I must confess, though, that I feel a bit queasy about it as I’m depending on the service provider always being there and continuing to forward masked email to my real address.

In practice – although I can’t understand why this should be the case – it seems to be usual for backscatter to happen only occasionally. You would think that the problem would get worse and worse as the bad guys keep re-using your email address, but it doesn’t seem to happen that way.

It could be that just understanding what is happening when you get backscatter will be enough for you to accept the minimal nuisance of it happening to you, without getting too paranoid about your cyberlife. In other words, just doing nothing except deleting backscatter as it arrives may be the best policy.

© 2011-2018 David Leonard
Computer Support in London
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