On spam, bbc news, and maliciousness.

[senji]

ankaret posted a locked article expressing befuddlement at this BBC news article expressing befuddlement about:
You shouldn't open a spam e-mail, because as soon as you open the e-mail up, it notifies the organisation that has sent that, saying this is a valid e-mail address. They know how long you've looked at it, when you looked at it and did you go

Comments

[hmmm_tea]

I have to use outlook at work. When I get an email with a return receipt request, it pops up a dialog and asks me whether I want to send a receipt (I think you can get it to send them as default, but it certainly looks as if outlook's default is to ask).

[senji]

What would Outlook consider "the current domain" to be in this context?

[king_of_wrong]

Except that Outlook / Outlook Express haven't automatically downloaded the files in years - the "images not downloaded, for your protection" bar has been around longer than WinXP, IIRC.

Agreed on the technical analysis, though. It was a valid way for spammers to identify valid addresses, it was used in the wild, and it's now hopefully been plugged by everyone writing MUAs...

[shadowphiar]

Another technique (which requires users to download attached images from remote webservers) is to put an image somewhere small and unobtrusive, with width and height specified in the html (so the page displays before it is downloaded). The image file itself is very large, but served very slowly by a specially configured webserver, getting only a few bytes per second. That way, the connection doesn't get closed for as long as the email window is open and the client is trying to still trying to finish rendering it. The webserver can measure how far through the file each client actually got, assuming that the end point is when the window was closed.