Social engineering scams involve a mix of technical skills and psychological manipulation. Chris Cardinal discovered someone running such a scam on Amazon using his account: the scammer contacted Amazon pretending to be Chris, supplying his billing address (this is often easy to guess by digging into things like public phone books, credit reports, or domain registration records). Then the scammer secured the order numbers of items Chris recently bought on Amazon. In a separate transaction, the scammer reported that the items were never delivered and requested replacement items to be sent to a remailer/freight forwarder in Portland.
The scam hinged on the fact that Gmail addresses are "dot-blind" (firstname.lastname@example.org is the same as email@example.com), but Amazon treats them as separate addresses. This let the scammer run support chats and other Amazon transactions that weren't immediately apparent to Chris.
Others have reported on this scam, but word hasn't gotten around at Amazon yet, and when Chris talked to Amazon reps to alert them to the con, they kept insisting that his computer or email had been hacked, not understanding that the con artist was attacking a vulnerability in Amazon's own systems.
A little bit of sniffing finds this thread where users at a social engineering forum are offering to buy order numbers. Why? Because as it turns out, once you have the order number, everything else is apparently simple.
If you’ve used Amazon.com at all, you’ll notice something very quickly: they require your password. For pretty much anything. Want to change an address? Password. Add a billing method? Password. Check your order history? Password. Amazon is essentially very secure as a web property. But as you can see from my chat transcript above, the CSR team falls like dominoes with just a few simple data points and a little bit of authoritative prying.