We know where you surfed last night – cookies and privacy

That Man Smith takes aim at the use of cookies in email

A group of privacy advocates led by security expert Richard Smith and Junkbusters president Jason Catlett is lobbying the Federal Trading Commission to force software companies to close a cookie security loophole that allows Web surfing habits to be tracked by the use of email. Smith, whose previous scalps include security 'issues' involving RealPlayer and Microsoft, has as usual provided a convincing explanation of how the loophole can be exploited.

The loophole is available via email clients that can display graphics retrieved from the Web. You read the message, the graphic is downloaded, and you can then be assigned a unique serial number via a cookie. The serial number can be matched to your email address (because the assigner of the cookie sent you the email, right?) and then you're effectively 'branded' -- as you browse Web, any site with access to the data cross-referencing the cookie with your email ID knows who you are. You can get further details from Smith.

One of the mechanisms companies use to simplify this process, say Smith, is to encode the recipient's email address in the URL of the graphic, making it easy for their servers to match the cookie to the address.

Catlett, who slings a mean sound-bite, says that "Cookie leaks are the bug from spammers that keeps on bugging. It's intolerable that email can be used to silently zap a nametag onto you that might be scanned by a site you visit later. It's like secretly barcoding people with invisible ink." Smith has called on Netscape, Microsoft and other software companies to patch the hole, and has sent a report to the FTC. ®

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